To bill as an independent contractor, you send the client a written, itemized invoice on the payment terms you agreed to in your contract, collect payment through a method that doesn’t eat your margin, and set aside a portion of every payment for the taxes no one is withholding for you. The mechanics are simple once they’re in place, but every step depends on the one before it: no contract means no leverage, no W-9 means no payment processed, no tracking means no clean tax return.
Lock the Paperwork Before You Invoice
The biggest invoicing mistake happens before the invoice exists: starting work without a written agreement. A contract doesn’t need to be long, but it should pin down the scope of work, your rate or project fee, the payment schedule, and what happens if the client pays late or cancels. Without that written foundation, an unpaid invoice becomes a “he said, she said” dispute with almost no leverage on your side. A signed agreement is strongest, but even an email exchange confirming terms is far better than nothing.
Your client also needs your tax information before they can cut a check. Most businesses require a completed IRS Form W-9 before paying any contractor. The form provides your Taxpayer Identification Number, which the client uses to report what they paid you to the IRS at year’s end.1Internal Revenue Service. About Form W-9, Request for Taxpayer Identification Number and Certification You can use either your Social Security number or an Employer Identification Number on the W-9. An EIN is worth getting if you’d rather not put your Social Security number on documents that pass through multiple hands. The IRS lets you apply online at no cost, and the number is issued immediately.2Internal Revenue Service. Get an Employer Identification Number
What Every Invoice Should Include
A professional invoice works as both a payment request and a financial record. Missing any of these elements creates friction that delays payment or causes bookkeeping headaches months later.
- Your full legal name or registered business name, mailing address, phone number, and email. Include your EIN if you have one.
- The client’s business name, billing address, and the name of a specific contact in accounts payable.
- A unique invoice number that follows a consistent format. Sequential numbering like INV-2026-001 or a date-based format both work, as long as no two invoices share a number.
- The invoice date and an explicit payment due date. Don’t force the client to calculate it.
- Line-item descriptions showing what you did, when, the quantity (hours or deliverables), and the rate. A single lump sum with no detail invites questions and delays.
- The total amount due, with line items summed, any sales tax added, deposits subtracted, and the final balance shown clearly.
Detailed line items do double duty. They help the client understand exactly what they’re paying for, and they build the documentation the IRS expects if you ever need to substantiate business expenses. The tax code allows deductions for ordinary and necessary business expenses only when you can prove them, and invoices are part of that proof.3Taxpayer Advocate Service. Trade or Business Expenses Under IRC 162 and Related Sections
Accounting software like QuickBooks or FreshBooks handles the formatting for you, but a well-built spreadsheet template works too. The tool matters less than the consistency. Pick one format and stick with it so your records are searchable when tax season arrives or a client questions a charge.
Setting Payment Terms and Late Fees
Payment terms belong on every invoice, not just in the contract. State them plainly.
“Net 30” is the most common, giving the client 30 calendar days from the invoice date to pay. “Net 15” and “Net 60” are also standard, and “due upon receipt” means immediately. Large companies with formal accounts-payable departments rarely pay faster than Net 30 no matter what the invoice says, so factor that reality into your cash flow planning.
Late fees give clients a financial reason to pay on time. A charge of 1% to 2% per month on the unpaid balance is standard in most industries. Disclose the late fee on the invoice itself and, ideally, in the original contract. A late fee that appears for the first time on a past-due notice is much harder to enforce.
If cash flow matters more to you than the full invoice amount, an early payment discount can shorten the wait. A term like “2/10 Net 30” means the client can take a 2% discount if they pay within 10 days; otherwise the full amount is due in 30. On a $5,000 invoice, that discount costs you $100 but can shave weeks off collection.
How Clients Can Pay You
How you get paid affects how much of each invoice you actually keep.
- ACH bank transfers move money directly between bank accounts, usually within one to three business days. Fees are low or zero for the receiver, which makes ACH the most cost-effective option for routine work. You’ll need to share your bank name, routing number, and account number.
- Wire transfers arrive faster, sometimes the same day, but domestic wires typically cost $25 to $30 per transaction. They fit large one-time payments where speed matters.
- Digital payment platforms are convenient but expensive. Stripe charges around 2.9% plus 30 cents per card transaction, and PayPal’s rates run from 2.99% to 3.49% plus a 49-cent fixed fee depending on the transaction type. A 3% cut on a $10,000 invoice is $300 you never see.4Stripe. Pricing and Fees5PayPal. Fees – Merchant and Business
- Checks still turn up, particularly from government agencies and older firms. No processing fee, but clearing takes days and you’re at the mercy of the mail.
List your preferred payment method and the necessary account details right on the invoice. When a client has to email asking where to send the money, you’ve already lost a week.
Sending the Invoice and Tracking It
Always convert your invoice to PDF before sending. A Word document or spreadsheet can be edited, which opens the door to disputes about what the invoice originally said. A PDF locks the content and looks more professional.
Email is the default delivery method for most freelance and consulting work. Use a subject line that references the invoice number and project, something like “Invoice #2026-003 — Website Redesign Phase 2.” Keep the body brief: a sentence confirming the attachment, the total, and the due date. The email itself creates a time-stamped record of delivery. Some larger clients will require you to submit through a vendor portal instead; follow their process exactly and save a confirmation number.
Log every invoice you send with the date, amount, and expected payment date. Accounting software does this automatically; a spreadsheet works if you update it consistently. At the end of each month, compare your bank deposits against outstanding invoices to catch anything that slipped through.
Hold on to invoices, receipts, contracts, and payment records for at least three years. The IRS requires you to keep documents supporting income, deductions, or credits until the statute of limitations for that return expires, which is generally three years from the date you filed.6Internal Revenue Service. How Long Should I Keep Records
When a due date passes, follow up quickly. A polite reminder three to five business days after the due date, with the invoice attached, resolves most late payments. Invoices get lost in inboxes, approvals stall, someone goes on vacation. A quick nudge usually clears it.
Deposits, Retainers, and Reimbursable Expenses
For larger projects or new client relationships, collecting money upfront reduces your risk. A deposit is a partial payment applied toward the total project fee. On an $8,000 project, requesting 25% or 50% before starting work means you’re not fully exposed if the client disappears.
A retainer works differently. It’s a fee the client pays to secure your availability over a set period, and it’s typically nonrefundable. Retainers fit ongoing advisory or creative work where the client needs guaranteed access to your time. Your contract should specify whether unused hours roll over or expire and whether the retainer covers a set number of deliverables or just availability.
If your contract lets you pass through costs like materials, travel, software, or subcontractor fees, list them as separate line items with the date incurred, a description, and the exact amount. Attach receipts. Whether you can mark up reimbursables depends entirely on what the contract says; some clients expect pass-through at cost, others accept a handling fee. Settle that in writing before you incur the expense, not after. Keep the reimbursable section visually distinct from your service fees so the client can see at a glance what’s labor and what’s out-of-pocket.
When a Client Won’t Pay
If reminders don’t work, escalate. Start with a formal demand letter that identifies the unpaid invoice, states the exact amount owed (including any accrued late fees), sets a firm deadline, and warns that you’ll pursue legal action if the balance isn’t settled. Send it by certified mail so you have proof of delivery. A demand letter often shakes loose payments that polite emails couldn’t, because it signals you’re serious.
If the demand letter gets no response, small claims court is the most accessible option. Dollar limits vary by state but generally range from $10,000 to $30,000. You don’t need a lawyer, filing fees are modest, and the process is designed to be straightforward. Invoices above your state’s small claims limit require civil court, where costs and complexity climb.
One boundary worth knowing: the Fair Debt Collection Practices Act, which restricts how debts can be collected, applies only to personal debts. It does not cover business-to-business debts, so it won’t help you if a client refuses to pay your invoice.7Consumer Financial Protection Bureau. What Laws Limit What Debt Collectors Can Say or Do Your recourse is contract law and the courts, which is another reason the written agreement matters so much.
Taxes on What You Invoice
Every dollar a client pays you is self-employment income, and the IRS expects you to handle the taxes yourself.
Self-Employment Tax
Contractors pay self-employment tax at a combined rate of 15.3%, covering the Social Security portion (12.4%) and the Medicare portion (2.9%).8Internal Revenue Service. Self-Employment Tax (Social Security and Medicare Taxes) Employees split these taxes with their employer; you owe both halves. For 2026, the Social Security portion applies only to the first $184,500 in net earnings, and Medicare has no cap.9Social Security Administration. Contribution and Benefit Base You calculate this tax on Schedule SE and file it with your annual return.10Internal Revenue Service. About Schedule SE (Form 1040), Self-Employment Tax
Quarterly Estimated Payments
Because nobody withholds income tax or self-employment tax from your invoices, you pay estimated taxes four times a year. For the 2026 tax year, the deadlines are April 15, June 15, September 15, and January 15, 2027.11Taxpayer Advocate Service. Making Estimated Payments Miss them and you face an underpayment penalty calculated on the shortfall and the period it went unpaid.
You can generally avoid the penalty if you owe less than $1,000 at filing time, or if you’ve paid at least 90% of your current-year tax or 100% of last year’s (110% if your prior-year adjusted gross income exceeded $150,000).12Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty A workable rule for new contractors: set aside 25% to 30% of every invoice payment in a separate savings account for taxes. Adjust once you have a year of actual numbers to work from.
The 1099-NEC
Any client who pays you $600 or more during the tax year is required to report those payments to the IRS on Form 1099-NEC.13Internal Revenue Service. Instructions for Forms 1099-MISC and 1099-NEC You should receive a copy by January 31 of the following year. You owe taxes on all your contractor income regardless of whether a client sends you a 1099. The form is for reporting, not a trigger for tax liability. Your invoicing records should match or exceed what the 1099s report, which is why the tracking habits you build during billing pay off directly at tax time.