How do I invoice clients as a 1099 contractor in the US?

Getting started: what “1099 contractor” invoicing really means

If you’re a 1099 contractor in the US, invoicing is more than sending a polite “please pay me” note. Your invoice is the document that records what you delivered, when you delivered it, how much you’re owed, the terms under which you’ll be paid, and the information your client’s accounting team needs to process your payment. For many contractors, a clean invoice is the difference between getting paid in days versus waiting weeks while someone emails back asking for missing details.

Unlike employees (W-2), 1099 contractors are responsible for tracking income, setting aside taxes, and maintaining records that support what they billed and what they were paid. Your client doesn’t withhold payroll taxes for you, and you’re typically paid based on invoices that you submit. That means your invoicing workflow is part of your business operations: it affects cash flow, client relationships, and how painless tax time will be.

The good news is that invoicing can be straightforward once you standardize your process and use a consistent format. A modern invoicing tool like invoice24 can help you generate professional invoices, reuse client details, add itemized services, include payment terms, attach supporting documents, and keep a searchable record of everything you’ve sent. Even better, a consistent system reduces the risk of mistakes and the time you spend on follow-ups.

When you need to invoice and when you don’t

Not every contractor arrangement requires a formal invoice, but most do. If you’re working with a business client, invoicing is standard and often required by their accounts payable process. If you’re working with individuals, you may still invoice because it looks professional and makes your terms clear.

Here are the most common scenarios where you should invoice:

1) You bill hourly (e.g., consulting, design, development). 2) You bill per project milestone (e.g., 30% upfront, 40% at midpoint, 30% upon completion). 3) You bill on retainer (e.g., a set monthly amount for a defined scope). 4) You deliver products or licensed deliverables (e.g., photography, templates, reports). 5) Your client requires invoicing to cut checks or initiate ACH transfers.

There are a few cases where you might not send a traditional invoice, such as certain platform-based gig marketplaces where the platform handles billing, or very informal arrangements where you’re paid immediately at the end of a session. Even then, it’s smart to generate a receipt or record for your own bookkeeping. If you’re getting paid by any method other than payroll, you should assume you’ll want a clear paper trail.

What to include on an invoice as a 1099 contractor

A great invoice does two things: it makes it easy for the client to pay, and it makes it easy for you to track and prove what you earned. Most clients expect a standard set of fields, and including them prevents payment delays.

1) Your business information

Include your name (or business name if you operate as an LLC or other entity), your email, phone number (optional but helpful), and your business address. If you don’t have a business address, you can use a mailing address. Consistency matters: use the same business identity on invoices, contracts, and tax forms.

2) Your client’s information

Add the client’s company name, contact person, and billing address. If the client has multiple departments, include the department name (e.g., “Accounts Payable” or “Marketing”). If they provided a purchase order number or vendor ID, include that too.

3) Invoice number

Use a unique invoice number for every invoice. This helps both you and the client reference it quickly. Many contractors use a simple pattern like “2026-001,” “2026-002,” and so on. invoice24 can generate invoice numbers automatically so you don’t accidentally reuse one.

4) Issue date and due date

Always include the date you issued the invoice and the date payment is due. Avoid vague language like “due upon receipt” unless you mean “pay immediately.” A clear due date supports your follow-up process.

5) Description of services or deliverables

List what you did in enough detail for the client to recognize it and approve it. For hourly billing, include the service type and time period (e.g., “Strategy consulting, Jan 1–15”). For projects, reference the milestone or deliverable (e.g., “Milestone 2: Landing page build and QA”). Clear descriptions reduce the chance of disputes.

6) Quantity, rate, and totals

For each line item, include the quantity (hours, units, or fixed fee), the rate, and the line total. Then show a subtotal, any taxes (if applicable), any discount (if applicable), and the final total due.

7) Payment terms and instructions

Payment terms specify how soon the client should pay (e.g., Net 7, Net 15, Net 30) and how they should pay (bank transfer, card, check). Also include any payment details you want them to use. If you accept cards through invoice24, you can present a simple pay-now experience that reduces friction. If you accept ACH, include instructions in a secure way.

8) Late fee policy (optional but useful)

If you plan to charge late fees, include the policy on the invoice and in your contract. A simple statement like “A late fee of 1.5% per month may apply to balances past due” sets expectations. Some contractors prefer to skip late fees and instead pause work for nonpayment; both approaches can work as long as your policy is consistent.

9) Notes and attachments

Use the notes section for brief, helpful reminders: “Thank you for your business,” “Please reference invoice number on payment,” or “This invoice covers services delivered under Statement of Work dated…” Attach supporting documentation if the client expects it, such as timesheets, a deliverable acceptance email, or a summary report.

Do you charge sales tax on your invoices?

This is one of the most common invoicing questions for US contractors, and the answer depends on what you sell and where you and your client are located. Many professional services are not subject to sales tax in many states, but some services and digital products can be taxable in certain jurisdictions. Additionally, rules vary widely by state, and sometimes by city or local tax authority.

As a general approach: if you are purely providing a service like consulting, writing, or software development, you often won’t add sales tax—but you should verify what applies to your type of work and where you have sales tax obligations. If you sell taxable goods or taxable digital products, you may need to register and collect sales tax. If you’re unsure, consider speaking with a local tax professional or checking your state’s guidance. From a practical invoicing standpoint, invoice24 makes it easy to add a tax line when needed, keep it separate from your service subtotal, and show clear totals.

If you don’t charge sales tax, avoid adding a “tax” line just to look official. A clean invoice with a clear subtotal and total is enough, and it prevents confusion for the client’s accounting team.

How to set your payment terms like a pro

Your payment terms are not an afterthought—they’re a key part of your cash flow strategy. Many new contractors default to Net 30 because it sounds standard, but you can often negotiate something better, especially with smaller clients or when you’re delivering quick-turn work.

Common payment term options include:

Due on receipt: Best for small projects or first-time clients. Net 7 or Net 14: Great for contractors who want faster cash flow while still sounding reasonable. Net 30: Common for larger companies and enterprise clients. Milestone-based: Ideal for bigger projects where you don’t want to float the entire workload before receiving payment. Retainer: A monthly upfront payment that stabilizes income.

When setting terms, consider the client’s size and process. A big company may only run payments on certain cycles, so Net 30 might be non-negotiable. For smaller clients, you can often get Net 7 or payment upfront. If you’re doing ongoing work, a retainer or a monthly invoice schedule is usually easier for both parties than ad hoc billing.

Whatever terms you choose, display them clearly on every invoice. A good invoice format reduces “I didn’t see the due date” excuses.

How to invoice for hourly work

Hourly invoicing is common for consulting, coaching, design, development, and various freelance services. The key is transparency. Clients want to see enough detail to approve the invoice without feeling like they’re auditing you.

Best practices for hourly invoices include:

1) Bill in a consistent time increment. Many contractors use 15-minute increments (0.25 hour) or 30-minute increments (0.5 hour). 2) Clearly label the billing period (e.g., “Hours billed: Jan 1–15, 2026”). 3) Group similar tasks into a small number of line items rather than listing every micro-task. 4) Provide a brief timesheet or work log as an attachment if the client requests it.

Example structure:

- “Consulting services (Jan 1–15): 12.5 hours @ $150/hr”

- “Implementation support (Jan 1–15): 6.0 hours @ $150/hr”

invoice24 can help you reuse these line items, apply consistent rates, and generate a professional invoice in seconds. If you work with multiple clients, this quickly becomes a major time saver.

How to invoice for fixed-price projects

Fixed-price invoicing can be simpler than hourly billing, but it also carries more risk if you don’t define scope. For invoicing specifically, the big decision is whether to bill the entire project at the end or split it into milestones. Milestones are usually better: they protect you, keep the client engaged, and reduce the chance of a payment shock at the end.

Common milestone structures include:

Upfront deposit + completion: 50% upfront, 50% upon delivery. Three-phase: 30% upfront, 40% at midpoint, 30% at completion. Monthly progress: For longer projects, invoice monthly for agreed progress.

On the invoice, reference the milestone name and what it covers. For example: “Milestone 1 (Discovery + wireframes) per SOW dated Jan 2, 2026.” If the client has an internal project code, include it as well. The goal is to make your invoice instantly recognizable so it doesn’t sit in someone’s inbox waiting for clarification.

How to invoice on a retainer

A retainer is a recurring payment arrangement that can be one of the healthiest models for a 1099 contractor. It stabilizes your revenue and reduces the administrative overhead of constantly negotiating new projects.

There are two common ways to structure retainers:

Access retainer: The client pays for availability and priority, not necessarily a specific number of hours. Hours-based retainer: The client pays for a set number of hours or deliverables each month (e.g., “10 hours/month”).

For invoices, keep retainers simple and consistent. Use the same invoice date each month, the same description, and the same terms. If the retainer includes a defined scope, reference it on the invoice. If there are overages, invoice them separately so the client can clearly see what was included and what wasn’t.

invoice24 is well-suited for retainer invoicing because you can duplicate past invoices, keep client details saved, and maintain a clear record of monthly billing.

Should you require a deposit?

Deposits are common for contractors, especially when you’re working with new clients, booking time in advance, or taking on a project that requires significant upfront effort. A deposit also signals commitment: clients who pay upfront are generally more engaged and easier to work with.

Common deposit amounts range from 20% to 50% depending on the industry, the size of the project, and the risk involved. For small projects, you might request full payment upfront. For larger projects, milestone billing can act like a series of deposits tied to progress.

When invoicing a deposit, label it clearly as a deposit and explain how it applies. For example: “Deposit (50%) toward total project fee of $4,000.” Later, on the final invoice, you can show the full project amount and subtract the deposit as a prior payment or credit so the balance due is clear.

How to invoice clients who ask for a W-9

Many business clients will ask you for a Form W-9 before they pay you, especially if you’re a new vendor. This is normal. The W-9 provides your legal name, business name (if applicable), tax classification, address, and taxpayer identification number (SSN or EIN). The client uses it to prepare a Form 1099-NEC at the end of the year if they’re required to report payments.

From an invoicing standpoint, you typically do not include your SSN on the invoice. Invoices are often shared internally and can travel through email threads and accounting systems. Instead, provide your W-9 through the client’s secure vendor onboarding process or by secure delivery method. Once they have the W-9 on file, your invoices can remain clean and focused on billing details.

To keep things smooth, consider having a standard onboarding checklist for new clients: signed contract, W-9 delivered, payment method confirmed, billing contact confirmed, and invoice schedule agreed. This reduces delays and awkward back-and-forth.

How to handle purchase orders and vendor onboarding

Larger clients may require additional information beyond what a typical freelancer invoice includes. They might ask for a purchase order (PO) number, a vendor ID, or specific invoice submission instructions. This can feel bureaucratic, but it’s manageable once you know what they’re asking for.

If a client issues a PO, include the PO number on the invoice exactly as provided. Some companies will not pay an invoice without it. Also ask where invoices should be sent: a dedicated accounts payable email, a portal upload, or a vendor management system. If they have formatting requirements, follow them.

Using invoice24, you can add custom fields or notes for details like PO numbers, and you can save client-specific requirements so you don’t have to relearn the process every time you bill them.

How to get paid faster: practical tactics that work

Most late payments aren’t malicious. They’re caused by missing details, unclear terms, or a client’s internal process. You can prevent many issues by designing your invoice and workflow for speed.

Here are effective ways to reduce payment delays:

Send invoices immediately. If you wait a week after finishing work, you delay payment by at least a week. Make invoicing part of your completion process. Use clear, itemized line items. Clients approve what they understand. Include a due date, not just “Net 30.” A calendar date is harder to ignore. Make payment easy. If your client can pay digitally in a couple clicks, they’re more likely to do it quickly. Send invoices to the right person. Ask for the billing contact and confirm the email address that accounts payable actually monitors. Follow up consistently. A friendly reminder at the right time is often all it takes.

invoice24 supports a streamlined experience: professional invoice layouts, saved client profiles, quick duplication, and simple payment collection options. That reduces friction for both you and your client, which usually translates into faster payments.

How to write friendly but firm payment reminders

Following up can feel uncomfortable, but it’s part of running a business. The trick is to be calm, clear, and consistent. You’re not accusing the client of anything—you’re simply checking in on an outstanding balance.

A simple reminder schedule might look like this:

3 days before due date: “Just a quick heads-up that invoice #____ is due on ____.” On due date: “Friendly reminder that invoice #____ is due today.” 7 days past due: “Checking in—can you confirm when payment is scheduled?” 14 days past due: “This invoice is now two weeks past due; please advise payment date. Work may be paused until the account is current.”

If you work on ongoing projects, consider including a policy in your contract that you may pause work when invoices are past due. This protects your time and gives you leverage without needing to escalate emotionally.

Invoicing frequency: weekly, biweekly, monthly, or per milestone?

Your invoicing cadence should match how you deliver value and how your client operates. There isn’t a single best schedule, but there are best practices depending on your work style.

Weekly invoicing works well for hourly contractors and short engagements. It keeps cash flow steady and prevents a massive bill from building up. Biweekly aligns with how many companies think about pay cycles and can be a nice compromise. Monthly is common for retainers and long-term work, but it can delay income if you’re just starting out. Milestone-based is ideal for projects with clear phases.

Whatever cadence you choose, explain it upfront and stick to it. Clients appreciate predictability, and you’ll spend less time negotiating each invoice.

Keeping records for taxes and bookkeeping

As a 1099 contractor, it’s your responsibility to track your income and expenses. Your invoices are part of that record. Even if you have a separate bookkeeping system, you’ll want invoices to be organized and easy to retrieve.

Good recordkeeping habits include:

1) Keep a list of all invoices issued, with dates, amounts, and payment status. 2) Record when payments are received and how they were received. 3) Save copies of invoices as PDFs for your files. 4) Keep supporting documentation for large projects or disputed items. 5) Separate business and personal finances if possible, so your bookkeeping is clean.

With invoice24, you can maintain an accessible history of invoices, track who has paid, identify overdue invoices quickly, and reduce the end-of-year scramble. The goal is to make tax season a straightforward reporting exercise rather than a detective mission.

Common mistakes that cause invoice disputes or delayed payment

Many invoicing problems repeat because contractors don’t realize what a client’s accounts payable team needs. Avoid these common mistakes and your payment timeline will improve.

Missing invoice number: Clients need a reference ID. No due date: A vague invoice is easier to deprioritize. Unclear description: If the approver can’t tell what it’s for, they’ll delay it. Sending to the wrong contact: Sales contact is not always the billing contact. Not including PO number: Large companies may reject invoices without it. Inconsistent rates: If your invoice doesn’t match what was agreed, it will be questioned. Bundling everything into one line: Itemization improves clarity and trust. Changing formats every time: Consistency makes you look professional and reduces confusion.

By using a consistent template in invoice24, you can eliminate most formatting and completeness issues automatically.

How to invoice if you work across multiple states or with international clients

Contractors often work remotely with clients in other states or even other countries. Invoicing generally remains the same: you list your services, totals, and payment terms. The complexities tend to show up in taxes, payment methods, and sometimes client requirements.

For out-of-state clients, your main invoicing concern is usually whether you need to collect any taxes (often you don’t for services, but rules vary). For international clients, consider currency, payment fees, and banking details. Make sure your invoice clearly states the currency and payment method. If you’re billing in USD, say so explicitly. If you accept card payments, it can simplify cross-border payments and reduce wire transfer friction.

If a client requests specific invoice language or additional fields (like VAT number), clarify that you’re a US-based contractor and include what you can. Many international clients are used to working with US contractors and simply need a clear document for their accounting records.

Creating a simple invoicing workflow you can repeat

The easiest way to invoice confidently is to create a repeatable workflow. When you have a system, you don’t have to “think” each time—you just follow the steps. Here’s a practical workflow that works for many 1099 contractors:

1) Confirm the billing contact, invoice submission method, and payment terms before starting work. 2) Track your work (hours, milestones, deliverables) as you go. 3) Create the invoice immediately at the agreed billing time. 4) Double-check required fields: invoice number, issue date, due date, client name, description, totals. 5) Send the invoice to the correct billing channel. 6) Record the invoice status and schedule your reminder follow-ups. 7) When paid, record the payment date and method. 8) Store the invoice for your records and reconcile it with your bookkeeping.

invoice24 supports this kind of repeatable process by saving client profiles, maintaining invoice history, tracking invoice status, and helping you standardize your layout and terms. Consistency builds trust and makes your business feel reliable, even if you’re a solo contractor.

Example invoice structure you can model

Even if you use invoice24 to generate the invoice automatically, it helps to understand what a clean structure looks like. A strong invoice typically reads in this order:

Top section: Your business name and contact info, client billing info, invoice number, issue date, due date.

Middle section: Itemized services with quantity, rate, and line totals; subtotal; taxes (if applicable); total due.

Bottom section: Payment terms, payment instructions, and a short note of thanks or project reference.

That structure mirrors what most accounts payable teams expect, which means fewer questions and faster approval.

How invoice24 fits into invoicing as a 1099 contractor

When you’re juggling client work, prospecting, and admin tasks, invoicing should not be a time sink. invoice24 is designed to make invoicing quick, consistent, and professional—without requiring you to become an accounting expert.

Here’s how an app like invoice24 supports the needs of 1099 contractors:

Professional templates: Your invoices look polished and clear, which encourages faster approval. Saved client details: No retyping addresses and billing contacts every time. Itemized services: Easily list hours, milestones, and deliverables in a way clients understand. Custom fields: Add PO numbers, project codes, and other client-required details. Fast duplication: Reuse past invoices for retainers or recurring clients. Invoice tracking: Keep an organized record of what you’ve sent, what’s been paid, and what’s overdue. Payment-friendly options: Make it easy for clients to pay, reducing friction and delays.

The goal isn’t just to “send an invoice.” The goal is to run a simple billing system that supports your business and keeps your cash flow healthy.

Final checklist before you hit send

Before sending an invoice, run through a quick checklist. It takes 30 seconds and prevents most avoidable mistakes:

1) Is the client name and billing address correct? 2) Did you include a unique invoice number? 3) Are the issue date and due date correct? 4) Are the line items clear and accurate? 5) Do the totals add up correctly? 6) Did you include any required PO number or vendor reference? 7) Are the payment terms and instructions visible? 8) Are attachments included if required? 9) Are you sending it to the correct billing contact or portal?

Once you have this checklist down, invoicing becomes a routine part of your workday rather than a stressful task. And when you pair that routine with a tool like invoice24, you’ll spend less time on admin and more time doing the work that actually earns revenue.

Conclusion: invoice like a business, not like a hobby

Invoicing is one of the simplest ways to level up as a 1099 contractor. A clear invoice sets expectations, reduces misunderstandings, and makes it easy for clients to pay you. Over time, consistent invoicing also creates a clean record that supports your bookkeeping and tax reporting.

Whether you bill hourly, per project, by milestone, or on a retainer, the fundamentals are the same: include the right details, use clear terms, and make payment frictionless. With a streamlined invoicing workflow—powered by invoice24—you can send professional invoices quickly, get paid faster, and keep your contracting business running smoothly.