How to Invoice Clients as a 1099 Contractor
If you work as a 1099 independent contractor in the United States, your invoice is the document that turns finished work into paid income. Unlike a W-2 employee on payroll, you have to issue, track, and chase invoices yourself — and clients increasingly route them through accounts payable workflows that reject anything missing a TIN, a clear due date, or a remittance address. This guide walks through the W-9 setup, what every contractor invoice must contain, how to set sensible payment terms and late fees, and what to do when a client goes silent past net-30.
Step 1: Submit a W-9 before you start work
Before a US business pays a 1099 contractor more than $600 in a calendar year, they need a completed Form W-9 on file so they can issue you a 1099-NEC in January. Sending the W-9 proactively — ideally with your first invoice or as part of contract signing — avoids the awkward situation where a client holds payment until they have your TIN. Use your legal name and SSN (or EIN if you operate through an LLC), match the entity classification box to how you file taxes, and re-sign a fresh W-9 any time your name, address, or tax status changes.
Step 2: What every contractor invoice must include
A US contractor invoice is not regulated the way a VAT invoice is in Europe, but accounts payable teams will reject or delay invoices missing standard fields. Include all of the following, every time:
- A unique invoice number (sequential — "INV-2026-014" reads better than a random string)
- Your legal business name, address, and the same TIN you reported on the W-9
- The client's billing entity name and AP email or address
- Invoice date and a clear due date ("Net 30 — due June 18, 2026", not just "Net 30")
- Line items with description, quantity, rate, and line total
- Subtotal, any reimbursable expenses, and the grand total in USD
- Payment instructions: ACH details, check mailing address, or a Stripe/PayPal link
Step 3: Pick payment terms that actually get paid
Net-30 is the US default but it's negotiable. Many independent contractors use Net-15 or even "due on receipt" with new clients and only relax terms after the relationship is established. Larger enterprise clients will push back to Net-45 or Net-60 — be aware of the cash-flow cost before you agree. If a client wants extended terms, ask for a deposit (25-50% on signing) or a milestone schedule so you're not financing their entire project.
Step 4: Late fees and escalation
A late-fee clause in your contract gives you a lever when an invoice ages out. Common US norms: 1.5% per month (18% APR) on past-due balances, or a flat $25-50 reminder fee after the second past-due notice. Whatever you choose, restate the fee on the original invoice so it isn't a surprise. Escalation timeline that works for most contractors: friendly reminder at 7 days past due, formal demand letter at 30 days past due, switch to certified mail and reference the contract at 45 days, and consider small-claims court or a collections agency past 60-90 days. Most US small-claims courts handle disputes up to $5,000-$10,000 without a lawyer.
Step 5: Tracking everything for tax time
Keep a running log of every invoice issued, the date paid, and the payment method. At year-end, cross-check against the 1099-NEC forms your clients send you in late January — discrepancies happen and you want them resolved before April 15. If a client paid you via Stripe, PayPal, or a similar third-party processor, those amounts are reported on 1099-K, not 1099-NEC, but they still count as income.
Frequently asked questions
Do I need to charge sales tax on my services as a 1099 contractor?
It depends on your state and what you sell. Most pure services (consulting, writing, design) are exempt in most US states, but a growing number of states tax digital services and SaaS. If you sell software, SaaS, or tangible goods, check your state's rules and your nexus footprint. When in doubt, consult a CPA.
What if a client refuses to pay an invoice?
Document everything in writing, send a formal demand letter referencing your contract and the past-due amount, then file in small-claims court (most US states handle disputes under $5,000-$10,000) or engage a collections agency. A signed contract or signed statement of work dramatically increases your odds.
Do I send a 1099 to my clients, or do they send one to me?
Clients send a 1099-NEC to you (and to the IRS) by January 31 for any contractor they paid $600 or more in the prior year. You do not issue 1099s to your clients — you issue invoices.
Can I invoice in advance?
Yes. Deposit invoices, retainers, and milestone invoices are all standard for US contractor work. The invoice date drives when you recognize the income (cash basis) and when late fees start accruing.
What payment methods should I accept?
ACH bank transfer is the cheapest for both sides for invoices over $500. Stripe, PayPal, and Square charge 2.9% + $0.30 but speed up cash flow on smaller invoices. Avoid taking checks unless you're working with a client who insists — the float kills your cash cycle.
This guide is general information about US contractor billing and does not constitute tax or legal advice. Consult a CPA or tax attorney for your specific situation.
