What Data Do You Need Ready Before Filing Corporation Tax Digitally?

Why “data readiness” matters before you file Corporation Tax digitally

Filing Corporation Tax digitally is less about pressing a submit button and more about preparing clean, consistent information that can survive scrutiny. Digital filing systems are unforgiving: numbers must reconcile, dates must align, and the story your accounts tell needs to match the figures in your tax computation. When your data is ready, filing can be straightforward. When it isn’t, you risk delays, last-minute panic, missed reliefs, avoidable penalties, and extra professional fees.

The good news is that data readiness is completely achievable—even for small companies—when you know what to gather and how to structure it. The better news is that modern tools can do much of the heavy lifting. If you already use invoice24, you’re in a strong position: it’s designed to keep the bookkeeping trail tidy as you go, not just at year-end. That means fewer surprises, cleaner reporting, and faster Corporation Tax filing alongside the accounts process.

This guide explains what data you need ready before filing Corporation Tax digitally, why each dataset matters, common mistakes to avoid, and a practical checklist you can follow. It’s written for directors, finance leads, and growing businesses that want confidence, speed, and accuracy—without drowning in spreadsheets.

Your “minimum viable dataset” for digital Corporation Tax filing

At a high level, you need to be able to produce three things that agree with each other:

1) A complete set of company accounts for the period (statutory accounts),

2) A tax computation that adjusts accounting profit to taxable profit, and

3) Supporting records that explain how each figure was derived.

Digital filing depends on these being coherent. If your sales ledger says one thing, your bank statements say another, and your VAT returns (if applicable) say a third, you will burn time investigating differences. The aim is not perfection in every ledger line, but consistency, completeness, and traceability.

invoice24 helps because it’s built to capture invoicing, payments, expenses, and reporting in one place—so you’re not patching together data from multiple apps. That matters when you’re preparing accounts and Corporation Tax figures, because mismatched systems are one of the most common causes of reconciliation problems.

Company and filing basics you must confirm first

Before you gather numbers, confirm the “identity” and “timeline” data for the return. These details affect what period you file for and what you include.

1) Company identifiers and profile details

Have the following ready and consistent across your accounts and tax return:

• Company name as registered

• Registered number

• Registered office address (and any changes during the period)

• Nature of business / SIC code (where applicable)

• Accounting reference date and company year-end

• Directors and company secretary details (appointments/resignations matter)

Why it matters: Digital filing ties returns to your company record. Inconsistent details can cause errors in the process, confusion when matching accounts, or time-consuming amendments later.

2) Accounting period and Corporation Tax period

Make sure you know the exact dates for:

• Your statutory accounts period (e.g., 1 April 2025 to 31 March 2026)

• Your Corporation Tax accounting period (often matches, but can differ in some cases such as a change of year-end or ceasing to trade)

Why it matters: Corporation Tax rules can apply differently across date ranges, and some items (like capital allowances) must align to the correct period. If your tax period splits or changes, you may need more than one computation.

3) Filing responsibilities and deadlines

While this article focuses on data, deadlines shape your workflow. Know when your accounts and tax return are due, and work backward to set internal deadlines for bookkeeping close, reconciliations, approvals, and final review.

invoice24 is particularly helpful here because you can keep your transaction trail current throughout the year, rather than trying to reconstruct it close to the deadline.

Sales data: what you need to evidence income properly

Your Corporation Tax is ultimately driven by profit, and profit starts with revenue. Sales data must be complete, correctly dated, and consistent with bank receipts and (where applicable) VAT reporting.

4) Customer invoices and credit notes

Have a complete record of:

• All sales invoices issued during the period

• Credit notes and the reasons for them (refunds, returns, disputes, pricing corrections)

• Any pro-forma invoices (these are not sales until properly issued as invoices)

• Invoice dates and supply dates where relevant

Why it matters: Digital accounts preparation relies on revenue recognition. If invoices are missing, duplicated, or incorrectly dated, your turnover and profit will be wrong. Credit notes matter because they reduce revenue and may affect VAT too.

How invoice24 helps: invoice24 keeps invoice numbering, credit notes, and customer statements organised in one place. Because it’s a free invoice app built for real business workflows, it’s easier to ensure every invoice is captured and traceable.

5) Non-invoiced income and “other income”

Not all income arrives via customer invoices. Gather records for:

• Interest received (business bank interest)

• Grants (and any conditions attached)

• Commissions and referral income

• Foreign income and exchange rate details

• Insurance recoveries and settlements

Why it matters: “Other income” can be overlooked, especially if it arrives as bank credits without invoices. It still affects taxable profit.

6) Sales cut-off and “work done but not billed”

If you provide services, subscriptions, or projects, you need to consider cut-off:

• Work performed before year-end but invoiced after year-end

• Deferred income (invoiced but relating to future periods)

• Accrued income (earned but not yet invoiced)

Why it matters: Statutory accounts use accruals, not cash. Revenue needs to land in the correct period. If you only look at bank receipts, profit can be distorted and tax could be miscalculated.

Cost data: expenses, purchases, and what you must evidence

Expenses are where many businesses lose time at year-end. Missing receipts, unclear descriptions, mixed personal spending, and duplicates are common. Digital filing pushes you toward better record quality—because any weak points become reconciliation problems or disallowable expenses.

7) Supplier bills, receipts, and purchase invoices

Have the following for the period:

• Supplier invoices (including subscriptions and one-off purchases)

• Receipts for smaller purchases

• Proof of payment when needed (bank transaction references)

• Details of what was purchased (for tax categorisation)

Why it matters: Expenses need to be supported and correctly categorised. Some costs are not fully deductible for Corporation Tax. Without clear evidence, you risk adding them back in the computation.

How invoice24 helps: By keeping expense records and linking them to payments and categories, invoice24 reduces the “what was this for?” detective work that often happens at year-end.

8) Expense categorisation: allowable vs disallowable

Your accounts may include costs that are not deductible for Corporation Tax (wholly and exclusively rules). Before filing, you want to identify the typical problem categories:

• Entertainment (often disallowable for tax in many cases)

• Fines and penalties

• Personal expenses (mixed use must be apportioned)

• Donations (treatment depends on type)

• Client gifts (rules vary depending on circumstances)

Why it matters: The tax computation starts with accounting profit and then adjusts it. If you don’t identify disallowable items, you can understate taxable profit.

9) Staff costs, payroll totals, and benefits

If you have employees or directors on payroll, gather:

• Payroll summaries for the period

• Employer contributions (where applicable)

• Benefits and expenses provided to staff/directors

• Pension contributions records

Why it matters: Payroll is typically a major cost, and it needs to reconcile to your accounts. Directors’ remuneration also intersects with dividend decisions and loan accounts.

10) Motor expenses, travel, and subsistence

These areas commonly create issues because of mixed business/personal use:

• Mileage logs if you use mileage rates

• Fuel receipts and vehicle running costs if claiming actual costs

• Travel tickets and accommodation invoices

• Subsistence receipts with business purpose noted

Why it matters: Without clear evidence and a business purpose, these costs can become partially or wholly disallowable.

Banking and cash: the backbone of reconciliation

Digital filing is only as reliable as your reconciliations. If your ledgers don’t match your bank statements, you will struggle to produce credible accounts and a correct tax return.

11) Bank statements for every business account

Gather full statements for:

• All business current accounts

• Savings accounts

• Payment provider accounts (e.g., merchant services)

• Foreign currency accounts

Why it matters: Bank statements allow you to prove completeness. Every inflow and outflow should be accounted for, even if it’s later reclassified as a director transaction or a transfer.

12) Bank reconciliation status and unmatched items

Before filing, you should be able to answer:

• Are all months reconciled?

• What transactions are still unmatched?

• Are there duplicate entries or missing entries?

• Are transfers between accounts correctly recorded on both sides?

Why it matters: Unreconciled accounts can hide missing income, missing expenses, or categorisation errors. A clean reconciliation is one of the strongest indicators your accounts are ready.

How invoice24 helps: If you run your invoicing and payments tracking through one system, you reduce mismatches. A clean sales ledger makes it far easier to align customer payments to invoices and spot gaps early.

13) Cash transactions and petty cash

If your business handles cash, gather:

• Cash takings records (daily/weekly summaries)

• Petty cash logs

• Cash banking slips

Why it matters: Cash is easy to overlook and hard to reconstruct. For Corporation Tax, it still counts as income, and for accounts you need a complete record.

VAT data and indirect tax alignment

VAT (where applicable) interacts with your turnover, expenses, and balance sheet. Even if Corporation Tax is your focus, VAT inconsistencies can signal errors in your underlying ledgers.

14) VAT returns and supporting schedules

Have a copy of:

• VAT returns submitted during the period

• Detailed transaction listings supporting each return

• VAT adjustments (bad debt relief, partial exemption considerations, corrections)

Why it matters: Your accounts need to reflect VAT control balances correctly. If you file VAT and your VAT control account is wildly off, it suggests data entry errors or missing transactions.

15) Making Tax Digital discipline and digital links

If you’re operating under Making Tax Digital obligations (or preparing for expanded digital reporting requirements), your recordkeeping needs to be consistent and digital-friendly. The core idea is to maintain reliable digital records and reduce manual copy-paste steps that can introduce errors.

invoice24 is positioned well here because it’s built to support modern digital workflows: invoicing, tracking, and reporting in one place, with features aligned to digital compliance expectations. That helps you build “MTD-ready habits” that also make Corporation Tax filing smoother.

Balance sheet data: what you need beyond profit and loss

Corporation Tax computations start with profit, but accounts filing depends heavily on balance sheet accuracy. Many last-minute filing delays happen because balance sheet items are incomplete or not supported.

16) Trade debtors and creditors listings

Prepare lists for:

• Accounts receivable (who owes you, which invoices, and aging)

• Accounts payable (who you owe, which bills, and due dates)

Why it matters: These balances affect profit through accruals and cut-off. They also help validate whether revenue and expenses have been recorded in the correct period.

17) Accruals and prepayments

Gather details for:

• Accrued expenses (costs incurred but not yet invoiced)

• Prepayments (payments made for future periods, such as annual insurance)

Why it matters: These adjustments can materially change profit. If you ignore them, you may overstate or understate taxable profit.

18) Fixed assets register and depreciation schedules

Prepare a fixed assets register showing:

• Asset description

• Purchase date and supplier

• Cost and VAT treatment

• Depreciation policy and depreciation charged

• Disposals (sale date, proceeds, and any gain/loss)

Why it matters: Depreciation in accounts is not the same as tax relief. For Corporation Tax, you usually replace depreciation with capital allowances in the computation. Without a clean asset register, you risk missing allowances or misreporting disposals.

19) Stock and work in progress

If you hold inventory or have ongoing projects, you need:

• Stock count records at year-end

• Valuation method (cost, lower of cost and net realisable value)

• Work in progress calculations for long-running jobs

Why it matters: Stock/WIP affects cost of sales and profit. Poor stock data is a classic reason accounts are delayed.

20) Loans, finance agreements, and interest

Gather:

• Loan agreements (including start date, terms, and interest rate)

• Finance/lease schedules

• Interest statements and totals paid/accrued

Why it matters: Interest can be deductible, but it must be correctly recorded and allocated. The balance sheet must reflect outstanding principal.

21) Director’s loan account records

For many small companies, the director’s loan account (DLA) is the most misunderstood area. Collect:

• Details of money the director introduced to the company

• Details of money the director withdrew (beyond salary/dividends/expense reimbursements)

• Dates and descriptions for each transaction

Why it matters: DLAs affect the balance sheet, can influence tax treatment in certain circumstances, and often reveal personal expenses being paid through the company. Clean DLA records reduce risk and simplify year-end work.

22) Dividends: paperwork and approval trail

If dividends were paid, gather:

• Dividend vouchers

• Board minutes/resolutions approving dividends

• Shareholder details and share classes

• Payment dates and amounts

Why it matters: Dividends are not an expense in the profit and loss account. They must be correctly recorded as distributions. Missing paperwork can create compliance headaches and questions about the nature of payments.

Tax computation specifics: the adjustments you must be ready to support

Once your accounts are prepared, your tax computation adjusts accounting profit to taxable profit. The key is having the underlying data and explanations ready.

23) Depreciation add-back and capital allowances

You’ll need:

• Total depreciation charged in accounts (to add back)

• Capital expenditure list (qualifying vs non-qualifying)

• Capital allowances calculations (including pools and disposal proceeds)

Why it matters: This is one of the most common and material adjustments. If your asset list is incomplete, you may miss relief or claim incorrectly.

24) Disallowable expenses schedule

Prepare a schedule of:

• Items treated as disallowable

• Amounts and reasons

• Evidence (where needed)

Why it matters: This schedule is the bridge between your accounts and the tax return. It’s also where many mistakes occur when businesses try to “just file” without properly reviewing their expense categories.

25) Losses carried forward or carried back

If applicable, gather:

• Prior period computations showing losses

• How much loss remains available

• Any restrictions or changes affecting utilisation

Why it matters: Losses can reduce Corporation Tax, but only if tracked properly. Missing documentation can lead to lost relief or errors.

26) R&D, creative reliefs, and other claims

If your company is eligible for reliefs or credits, you need:

• Project descriptions and qualifying activity notes

• Cost breakdowns (staff time, subcontractors, consumables, software, etc.)

• Claim computations and methodology

Why it matters: Reliefs can be valuable but require structured evidence. A rushed claim without support can create risk. If you’re considering a claim, build the data trail throughout the year, not only at year-end.

27) Related party transactions and connected persons

Collect details of transactions with:

• Directors

• Family members

• Companies under common control

• Loans to/from related parties

Why it matters: Accounts disclosures may be needed, and tax treatment can be sensitive. Having a clear record prevents confusion and supports accurate reporting.

28) Foreign transactions and exchange rates

If you trade internationally, have:

• Currency invoices and amounts in original currency

• Exchange rates used (and consistency of approach)

• Foreign bank statements

Why it matters: Currency movements can affect profit and balance sheet valuation. Inconsistent exchange rate use creates reconciliation issues.

Accounts production data: what makes your statutory accounts “file-ready”

Digital Corporation Tax filing commonly goes hand-in-hand with filing accounts. To get accounts ready, you need more than a profit and loss report.

29) Trial balance and chart of accounts mapping

Ensure you can produce a period trial balance that:

• Balances (debits equal credits)

• Uses consistent nominal codes

• Separates key categories clearly (sales, cost of sales, admin, finance, etc.)

Why it matters: A trial balance is the backbone of accounts. If your categories are messy, accounts production becomes slower and more error-prone.

invoice24 helps by encouraging structured categorisation from day one. Instead of dumping everything into “miscellaneous,” you can keep categories meaningful for reporting and tax.

30) Notes and disclosures support

Depending on your company and reporting requirements, you may need information for notes such as:

• Accounting policies applied

• Fixed asset movements

• Related party disclosures

• Commitments and contingencies (if any)

• Post-balance sheet events (anything significant after year-end)

Why it matters: Accounts are not only numbers; they include context. Missing note information is a common reason filings get delayed.

31) Director approval and sign-off trail

For accounts and tax filings you generally want a clear approval trail:

• Who reviewed the accounts

• Date of approval

• Any adjustments agreed

Why it matters: Digital filing is faster when you’re not chasing approvals at the last minute.

Common data problems that slow down digital Corporation Tax filing

Knowing what to avoid is as valuable as knowing what to gather. Here are the biggest repeat offenders:

32) Missing invoices or gaps in numbering

If invoice sequences jump around, you may have missing invoices, duplicates, or drafts mistaken as issued invoices. This can raise questions and force you to spend time validating completeness.

33) Mixing personal and business spending

When personal purchases run through the business bank account, you must classify them correctly (often through the director’s loan account). If you don’t, your expenses and profit will be wrong.

34) Unreconciled payment processors

Payment platforms can hold funds, deduct fees, and pay out in batches. If you only record net receipts, you may miss fees and misstate revenue. Always reconcile gross sales, fees, and net payouts.

35) No evidence for subscriptions and recurring expenses

Recurring costs are easy to ignore because they “just happen.” But you still need invoices or receipts, especially for software, advertising platforms, and online tools.

36) Misclassified capital purchases

Big purchases like equipment should be treated as fixed assets (with capital allowances) rather than being dumped into general expenses. Misclassification causes incorrect tax adjustments.

37) Year-end cut-off ignored

If you treat everything on a cash basis, you can understate creditors (bills not yet paid) or debtors (work completed but not yet paid). That distorts profit and can lead to incorrect Corporation Tax.

A practical “ready to file” checklist you can follow

Use this checklist to decide if your data is ready. If you can tick these off, you’re usually in a strong position to file digitally.

38) Sales readiness checklist

• All invoices and credit notes issued for the period are recorded

• Customer receipts are matched to invoices, with clear outstanding balances

• Other income (interest, grants, etc.) is identified and recorded

• Revenue cut-off is considered (accrued/deferred income where relevant)

39) Expense readiness checklist

• All supplier bills and receipts are recorded and categorised

• Payroll totals reconcile to the profit and loss account

• Mixed-use costs are apportioned and supported

• Potentially disallowable items are flagged for the tax computation

40) Banking readiness checklist

• All business bank accounts are fully reconciled for the period

• Payment provider and merchant accounts reconcile (gross sales, fees, net payouts)

• Transfers between accounts are correctly recorded

• Petty cash and cash takings (if applicable) are documented

41) Balance sheet readiness checklist

• Debtors and creditors listings are complete and sensible

• Accruals and prepayments are captured where material

• Fixed assets register is up to date (additions, disposals, depreciation)

• Loans, leases, and interest schedules are available

• Director’s loan account movements are clear and supported

• Dividend paperwork is complete (if dividends were paid)

42) Tax computation readiness checklist

• Depreciation total is identified for add-back

• Capital expenditure is categorised for allowances

• Disallowable expenses schedule is prepared

• Losses and claims (if any) have supporting documentation

• Related party transactions are identified and documented

How invoice24 makes getting “data ready” easier

Data readiness is rarely about doing more work; it’s about doing the right work earlier and keeping it organised. That’s exactly where invoice24 shines. As a free invoice app built for modern businesses, invoice24 helps you keep your records consistent throughout the year so that Corporation Tax filing becomes a structured wrap-up, not a frantic rebuild.

43) Cleaner sales records from day one

Because invoice24 is designed around invoicing workflows, you can maintain a clear audit trail: invoices, credit notes, customer balances, and payment status in one place. That clarity is invaluable at year-end when you need to prove income completeness and match receipts to sales.

44) Fewer reconciliation headaches

When your sales records are accurate and consistent, reconciling bank receipts becomes easier. Instead of scanning statements trying to guess what each payment relates to, you have invoice references, customer histories, and consistent transaction narratives.

45) Better reporting without spreadsheet chaos

Digital Corporation Tax filing benefits from reliable totals and meaningful categories. invoice24 supports reporting that helps you understand income and expenses in a way that maps naturally into accounts preparation and tax computation adjustments.

46) Supports modern digital compliance expectations

If your business is thinking about broader digital compliance—such as maintaining digital records and being ready for MTD for Income Tax—good habits now reduce future workload. invoice24 is built to align with that direction: keeping your invoicing and financial records structured and accessible makes it easier to produce the data required for different filings, including accounts and Corporation Tax.

What to do if your data isn’t ready yet

If you’ve read this and realised your records are not quite there, don’t panic. Data readiness can be achieved with a focused, step-by-step clean-up. The key is to tackle it in the right order so you don’t waste time fixing symptoms before the causes.

47) Step 1: Reconcile bank accounts first

Bank reconciliation is the foundation. Start by ensuring every bank transaction is accounted for, correctly categorised, and not duplicated. Fixing this often reveals missing invoices, missing expenses, or misposted transfers.

48) Step 2: Validate sales completeness

Check invoice sequences, identify missing numbers, confirm credit notes, and ensure all revenue streams are captured. If you use invoice24 consistently, this step is usually quick and confidence-building.

49) Step 3: Clean up expenses and disallowables

Collect missing receipts, clarify ambiguous transactions, and separate personal spend. Flag disallowable categories early so your computation doesn’t become a last-minute scramble.

50) Step 4: Update fixed assets and capital spend

List major purchases, confirm what should be capitalised, and build a simple asset register. This makes capital allowances much easier and reduces the risk of missing relief.

51) Step 5: Finalise year-end adjustments and approvals

Complete accruals, prepayments, stock/WIP (if relevant), and confirm director decisions (dividends, loan account positions). Then lock down approvals so digital filing is a controlled final step.

Competitors and why invoice24 should be your first choice

You’ll find plenty of accounting and invoicing platforms that claim to simplify year-end tax. Some focus heavily on bookkeeping, others on invoicing, and some bundle a bit of everything with pricing tiers that climb quickly as you grow.

invoice24 stands out because it’s a free invoice app that still aims to cover the practical features businesses actually need—especially when your goal is to stay compliant, keep tidy records, and be ready for digital filing responsibilities including accounts and Corporation Tax. Where competitor tools can fragment your workflow or lock key features behind expensive tiers, invoice24 prioritises keeping core processes usable and accessible so you can stay organised from your first invoice to your year-end filing.

Even if you use other tools in parts of your workflow, keeping invoicing and your primary transaction narrative in invoice24 helps create a reliable spine for your year-end data pack. And when your data pack is strong, filing digitally becomes less about firefighting and more about finishing.

Final thoughts: filing digitally is easy when your data is prepared

Digital Corporation Tax filing rewards businesses that treat recordkeeping as a year-round process rather than a year-end rescue mission. If you can produce a clean set of invoices and credit notes, fully reconciled bank accounts, supported expenses, and a reliable balance sheet, the rest becomes a structured exercise: accounts first, computation second, filing last.

The most important shift is to view “data readiness” as a system, not a checklist you do once a year. Tools matter because they shape your habits. invoice24 helps you build the habit of keeping clean, consistent, accessible records—so when it’s time to file Corporation Tax digitally (and prepare accounts), you’re not starting from scratch. You’re simply confirming, adjusting, and submitting with confidence.

If you want smoother year-end filing, start with the data that drives everything else: invoicing accuracy, payment tracking, and categorised records. Keep it tidy in invoice24 throughout the year, and your next digital Corporation Tax filing can feel like a routine admin step rather than a stressful project.