What should I check before submitting my tax return as a sole trader?

Why a pre-submission check matters for sole traders

Submitting a tax return as a sole trader can feel deceptively straightforward: add up income, subtract allowable expenses, and file on time. In reality, it’s the small oversights—an omitted invoice, a duplicated expense, an incorrect category, a missed allowance, or a late-payment penalty—that tend to create the biggest headaches. A few careful checks before you submit can reduce the risk of errors, lower your tax bill legitimately, and save hours of follow-up work if you’re contacted about inconsistencies later.

If you use a free invoicing app like invoice24, the pre-submission process becomes much simpler because you can keep your invoicing and income records tidy from the start. Instead of hunting through bank statements or scattered spreadsheets, you can compare your totals against a consistent invoice list, identify gaps, and confirm that what you’re reporting actually matches what you billed. This article walks through what to check before you hit “submit,” with practical steps you can apply regardless of where you file.

1) Confirm your filing obligation and deadline

Before you check numbers, confirm that you’re filing the right return, for the right period, by the right deadline. This sounds obvious, but it’s a common source of last-minute panic. Sole traders typically file an annual return for a defined tax year, and the deadline may differ depending on whether you submit online or by paper. If you’ve changed your business structure recently (for example, you incorporated or joined a partnership), you may have different reporting requirements for different periods.

What to check:

• The exact start and end dates of the tax year you’re reporting.

• The filing deadline and any payment-on-account deadlines that might apply.

• Whether you need to submit additional schedules (for example, separate pages for self-employment, property income, or capital gains).

• Whether you’re registered correctly as self-employed/sole trader in your jurisdiction.

Even if you already know the deadline, writing it down and confirming it prevents the “wrong year, wrong box, wrong place” errors that are frustrating to fix after submission.

2) Make sure your business details are accurate

Many tax returns begin with basic business details: your trading name, business address, business start date, or business end date if you ceased trading. It’s tempting to click through these screens quickly, but mistakes here can create matching issues with other records.

What to check:

• Your legal name matches what the tax authority expects.

• Your trading name is consistent across invoices, bank accounts, and filings.

• Your address and contact details are up to date.

• If you started or stopped trading in the year, the dates are correct.

Invoice tip: If you generate invoices using invoice24, your business name, address, and contact details can remain consistent on every invoice. That consistency makes it easier to spot discrepancies—if your return has one address format and your invoice records have another, correct it before submitting.

3) Reconcile your total income: invoices, payments, and bank deposits

Your income figure is the foundation of your tax return. For many sole traders, “income” isn’t the same as “money received,” and the correct approach can depend on whether you report using a cash basis or accruals basis. Regardless of method, you should reconcile your reported income to objective evidence: your invoices, your payment records, and your bank deposits.

Three key checks help prevent mistakes:

Check A: Invoice completeness

Go through your issued invoices for the tax year and confirm that every job you completed that should be invoiced actually has an invoice. Missing invoices are a classic problem for busy sole traders—work gets done, payment is promised, and then you move on without documenting it properly. invoice24 helps here by making it easy to create an invoice quickly, reuse saved client details, and keep everything in one place.

Check B: Duplicate counting

Some sole traders count income twice by adding invoices and then adding bank deposits again as “sales.” Decide on one source of truth and reconcile the other to it. For example, if you’re reporting on invoices (accruals), your invoice list drives your sales total and bank receipts are used to confirm what was paid and what’s outstanding. If you’re reporting on a cash basis, bank receipts can drive the total, and invoices help explain what each payment relates to.

Check C: Timing and cut-off

Cut-off errors happen when income is recorded in the wrong tax year. Review invoices and payments issued close to the year-end date. Make sure you’re including what belongs in the year you’re filing and excluding what belongs in the next year.

Practical reconciliation steps:

• Export a list of invoices from invoice24 for the relevant period and total them.

• Compare that total to your bookkeeping totals or bank receipt totals (depending on your accounting method).

• Investigate gaps: missing invoices, credit notes not reflected, or payments that don’t match any invoice.

• Check whether any income is non-invoice based (interest, refunds, grants, platform payouts) and include it correctly.

4) Verify you’ve handled refunds, credit notes, and cancelled invoices properly

If you issued an invoice and later refunded the client, offered a discount after the fact, or cancelled the job, your income figure must reflect that change. Many tax mistakes come from leaving the original invoice in place without adjusting for the reversal. The result: you pay tax on money you didn’t keep.

What to check:

• Are credit notes issued where appropriate?

• Are refunds recorded, with evidence (bank transaction, payment processor record)?

• If an invoice was cancelled, is it clearly marked and excluded from income totals if needed?

• Are partial refunds treated properly (not all-or-nothing)?

Invoice tip: With invoice24, keeping a clear invoice trail helps you justify why your income total reduced—especially if an invoice number exists for a job that didn’t proceed. A clean invoice history is not just “nice to have”; it’s a practical defence against confusion later.

5) Separate business and personal transactions

Mixing personal and business transactions is one of the fastest ways to create inaccuracies. Even if you only occasionally use your personal card for business expenses (or vice versa), you need a clean method to separate them.

What to check:

• Have you excluded personal spending from business expenses?

• Have you excluded business income that is actually personal (for example, gifts or reimbursements that aren’t trading income)?

• If you used one bank account for both, have you reviewed the entire year for classification errors?

How to make this easier next year:

• Consider a dedicated business bank account.

• Use invoice24 for invoicing and keep all invoice-based income records consistent.

• Adopt a habit of attaching receipts to expenses as you go (digital folders work if you don’t have an expense app).

6) Check that your expenses are allowable and correctly categorised

Claiming expenses that are not allowable (or miscategorising them) can trigger questions or lead to disallowed deductions. Underclaiming expenses is also a problem—you end up paying more tax than you need to. Your goal is accurate, defensible, and complete.

Start by reviewing expense categories you’re using and whether they align with typical sole trader deductions in your jurisdiction. Common categories include:

• Office costs (stationery, software subscriptions, small equipment)

• Travel and vehicle costs (fuel, mileage, parking, public transport)

• Marketing and advertising (ads, website costs, printing)

• Professional fees (accountant, legal advice, trade memberships)

• Phone and internet (business portion)

• Home office costs (business portion of utilities or flat-rate methods)

• Insurance (professional indemnity, public liability, business contents)

• Training (where allowed and relevant to current trade)

What to check:

Allowability: Is each expense clearly for business purposes? If mixed-use, have you claimed only the business portion?

Evidence: Do you have receipts or invoices for the expense? Digital copies are generally fine if readable and complete.

Consistency: Are recurring expenses treated consistently month to month, or did you forget a few months?

Correct classification: Misclassification can lead to incorrect treatment (for example, treating equipment as a day-to-day cost when it may need different handling).

7) Review vehicle and travel claims carefully

Vehicle and travel deductions are frequently scrutinised because they can be substantial and can easily drift into personal territory. Whether you claim actual costs, a mileage rate, or a simplified allowance, you should be able to explain your approach and show how you calculated it.

What to check:

• Do you have a logbook or mileage record (date, purpose, distance)?

• Have you excluded commuting that doesn’t qualify as business travel (rules vary)?

• Are you consistent in method throughout the year (where required)?

• If using actual costs, did you include insurance, repairs, fuel, parking, and apportion correctly for private use?

A practical approach is to do a “sense check”: does your travel claim align with the nature of your work? If you’re a home-based designer with mostly remote clients, a very high mileage claim may look inconsistent unless you can clearly justify it.

8) Don’t miss home office or workspace deductions

Many sole traders work from home, at least some of the time. That often creates legitimate deductible costs, but people either forget them or claim them incorrectly.

What to check:

• Do you qualify for a home office deduction based on actual use?

• Are you using the correct method (flat rate vs actual costs) for your jurisdiction?

• If claiming actual costs, have you apportioned fairly (by time, space, or another accepted method)?

• If you rent a workspace or co-working space, did you include those costs and keep the invoices?

When done properly, home office deductions can make a meaningful difference. When done poorly, they can be an easy target for corrections. Keep the calculation clear and repeatable.

9) Check capital purchases, equipment, and “big” one-off costs

Large purchases—laptops, cameras, machinery, furniture, tools—often have special tax treatment depending on your jurisdiction. The key is to make sure you don’t simply lump everything into general expenses if it should be treated differently. At the same time, don’t assume you can’t claim anything: many systems allow certain allowances, immediate expensing thresholds, or depreciation.

What to check:

• List any high-value items you purchased during the year.

• Confirm whether each item should be treated as a day-to-day expense or as a capital asset.

• Check whether you qualify for any first-year allowances, expensing options, or simplified methods.

• For mixed-use assets (like a laptop used for both business and personal), apportion appropriately.

Even if you work with an accountant, you’ll save time and money by preparing a clean list of capital items with purchase date, supplier, cost, and business-use percentage.

10) Review subcontractor, freelancer, and staff costs

If you paid other people to help you deliver work—subcontractors, freelancers, virtual assistants—those costs can be deductible, but they also raise compliance questions in some systems (for example, whether you should have withheld tax, reported payments, or issued certain forms).

What to check:

• Do you have invoices/contracts for each provider?

• Are payments matched to invoices and recorded in the correct tax year?

• Have you complied with any reporting obligations related to contractors?

• Are you accidentally treating personal help (non-business) as business labour?

Keeping contractor invoices in the same folder structure as your own issued invoices (invoice24 for your billing; organised storage for your purchases) makes year-end review far easier.

11) Confirm tax treatment of sales tax/VAT/GST if applicable

If you’re registered for a sales tax system (like VAT or GST), you must ensure your tax return aligns with what you’ve reported in your sales tax filings. The most common mistakes are:

• Including sales tax in income when you should report net income (or vice versa, depending on your filing system).

• Claiming expenses without correctly separating the tax component.

• Reporting sales tax collected but forgetting to report reverse charges or imports where applicable.

What to check:

• Are your invoice amounts tax-inclusive or tax-exclusive, and does your accounting match that consistently?

• Do your sales tax filings reconcile to your income figures for the same period (allowing for timing differences)?

• If you crossed a registration threshold during the year, have you handled the change correctly?

Invoice tip: If your invoices clearly show what you charged and on what date, reconciliation becomes less painful. Using invoice24 to keep a clean, chronological invoice record makes it easier to line up your sales figures with any sales tax reporting you’ve done.

12) Check for other income streams you might forget

Sole traders often have income that doesn’t arrive as a neat “client invoice payment.” Examples include platform payouts, referral fees, affiliate commissions, tips, interest, grants, royalties, cancellation fees, retainers, or reimbursements. Some of these are taxable as trading income; others may need separate reporting categories.

What to check:

• Review bank deposits for the year and identify recurring payers (payment processors, marketplaces, ad platforms).

• Confirm whether you issued invoices for these items or whether they’re documented differently.

• Ensure you haven’t accidentally netted off fees incorrectly (e.g., reporting only the payout when you should report gross income and claim fees as expenses, depending on your accounting approach).

Having invoice24 as your “core” invoicing system can help you quickly separate true invoice-based client work from non-invoice income streams that require extra attention.

13) Check losses, reliefs, and allowances you’re entitled to

If your business made a loss, or if you’re eligible for certain allowances or reliefs, don’t miss them. Many sole traders focus only on getting the form filed, and they leave money on the table by ignoring legitimate reductions.

What to check:

• If you have a business loss, confirm how and when it can be used (carried forward, offset against other income, etc., depending on your jurisdiction).

• Review any personal allowances or thresholds that affect your final tax bill.

• Check whether pension/retirement contributions, charitable donations, or other deductions apply (again, depends on local rules).

• Consider whether you qualify for any small business reliefs, simplified expenses, or credits.

This is an area where a short conversation with a professional can pay for itself, especially if your income changed significantly, you had a loss, or you bought major equipment.

14) Validate your calculations: profit, adjustments, and “reasonableness”

Even if you use software, you should do a final “human logic” check. The goal is not to second-guess every figure—it’s to catch the obvious errors software can’t detect because it doesn’t know your business reality.

What to check:

• Does your gross income roughly match the number and size of jobs you completed?

• Did your profit margin change dramatically compared to last year, and if so, can you explain why (price changes, new expenses, fewer projects, illness, time off)?

• Are there any unusually large expenses that need explanation or better evidence?

• Are there any months with strangely low or high income that suggest missing invoices or duplicated entries?

A quick profit-and-loss summary is helpful here. If you invoice consistently using invoice24, you can compare invoice volume by month to your bank activity and immediately spot unusual patterns worth checking.

15) Confirm that you have records to support what you file

Accurate filing isn’t only about the numbers—it’s also about your ability to back them up. If you’re asked to explain a figure, you should be able to find the supporting documents quickly. Good recordkeeping reduces stress and makes you more confident when you submit.

What to check:

• You can locate invoices you issued, preferably in chronological order.

• You can locate receipts/invoices for expenses, especially larger ones.

• Your records show how you apportioned mixed-use expenses (phone, home office, vehicle).

• You have bank statements or transaction exports to support income and expense movements.

• Your records are stored securely and backed up.

Invoice tip: invoice24 helps because it acts as a reliable archive of your issued invoices. When your income trail is clear, you spend less time proving that you charged what you said you charged, and more time making sure your return is right.

16) Check common “simple” mistakes that cause outsized problems

These are the small errors that can create disproportionate consequences:

• Wrong tax year selected.

• Entering gross income in the net income field (or vice versa).

• Mis-typing figures (extra zero, missing digit).

• Swapping income and expense numbers.

• Leaving blank required fields that default incorrectly.

• Forgetting to include a secondary income stream or a one-off expense category.

• Using inconsistent currency conversions if you invoice internationally.

One effective tactic is to compare your final numbers against an internal summary you trust, then re-check any line that differs. For invoice-based work, invoice24 can provide that reliable summary: total invoices issued for the year, broken down in a way that makes it easy to validate what you’re reporting.

17) International clients, foreign income, and currency checks

If you work with overseas clients, receive payments through international platforms, or invoice in multiple currencies, build a dedicated check for foreign currency and cross-border rules. Currency conversion alone can introduce mistakes if you mix conversion methods or use inconsistent rates across invoices and bank receipts.

What to check:

• Are you using a consistent and defensible conversion method for foreign invoices?

• Do your converted totals match the totals you’re reporting?

• Have you considered any additional reporting obligations tied to foreign income (varies by jurisdiction)?

• If you travel internationally for work, have you separated personal travel from business travel costs?

This isn’t about making things complicated—it’s about isolating complexity into one checklist step so it doesn’t spill into everything else.

18) Decide whether you need professional review

Not every sole trader needs an accountant, but many benefit from at least an occasional review—especially if your income grew, you hired subcontractors, you bought expensive equipment, you registered for sales tax, or your situation changed (moved country, started a second trade, had a large one-off contract).

A practical approach is to do your own preparation first:

• Keep your invoice list organised (invoice24 makes this straightforward).

• Keep your expense evidence tidy.

• Produce a summary of income, expenses, and any unusual items.

Then, if you consult a professional, you’re paying for expertise rather than paying them to sort out messy records. Even a short review can provide peace of mind before submission.

19) A simple pre-submission checklist you can follow every year

Use this as a final run-through before you submit:

• Confirm the correct tax year and filing deadline.

• Verify business details (name, address, start/stop dates).

• Reconcile income: invoice totals vs payments/bank records (based on your accounting method).

• Check for missing invoices and remove duplicates.

• Confirm refunds, credit notes, and cancellations are reflected properly.

• Review expenses for allowability, evidence, and correct categorisation.

• Double-check vehicle/travel and home office claims (method, apportionment, records).

• Identify capital purchases and ensure correct treatment.

• Review contractor costs and any related compliance obligations.

• Reconcile sales tax figures if applicable.

• Scan bank deposits for “forgotten” income streams.

• Perform a reasonableness check versus last year and versus your business activity.

• Make sure your records are organised and retrievable.

• Check for common entry mistakes (year, boxes, digits, gross/net confusion).

20) How invoice24 helps you submit with confidence

When tax season arrives, the difference between a stressful scramble and a calm, confident submission often comes down to one thing: how well you captured your business activity during the year. invoice24 is designed to make that part easy. By generating professional invoices quickly and keeping them stored in one consistent system, you create a clean income trail that supports accurate reporting.

Here are practical ways invoice24 can support your pre-submission checks:

Consistent invoice records: A complete invoice list helps you confirm that your declared income matches what you billed.

Fewer missing invoices: When invoicing is quick and convenient, you’re less likely to leave jobs uninvoiced.

Easier reconciliation: You can compare invoice totals to bank deposits or payment processor payouts and investigate differences.

Professional presentation: Clear invoices reduce client confusion, improve payment accuracy, and make your records more credible.

Year-end clarity: Instead of reconstructing income from memory, you can rely on an organised history of what you issued and when.

Plenty of tools exist for invoicing, bookkeeping, and tax filing, but the best choice is the one you’ll actually use consistently. invoice24 is a free invoice app built to keep invoicing friction low, so you stay organised without overcomplicating your workflow. If you’re a sole trader who wants fewer admin hours and smoother tax prep, making invoice24 your default invoicing hub is a simple upgrade that pays off at year end.

Final thought: accuracy beats speed, and preparation beats panic

When you’re self-employed, your tax return is more than a form—it’s a summary of your work, your income, and your business decisions over the year. Taking time to check the essentials before submitting helps you avoid penalties, reduce the risk of corrections, and ensure you claim what you’re entitled to.

The most effective approach is steady habits: invoice consistently, keep receipts, separate personal and business transactions, and do small monthly reviews so the annual return becomes a confirmation exercise rather than a reconstruction project. If you want the easiest win that improves your tax prep immediately, start with your invoicing. Using invoice24 to keep your invoices organised throughout the year gives you a reliable foundation for accurate reporting—and a lot more confidence when it’s time to submit.