How to write an invoice

An invoice has one job: tell a client exactly what they owe, for what, and by when, in a form their accounts team can approve without writing back to you. Below are the parts of an invoice in the order you fill them in, followed by a worked example with a discount, sales tax and a deposit.

Step by step

1. Your business details

Start with your legal business name, or the DBA name you registered if you trade under a different one, plus a mailing address, email and phone number. Clients use these details to set you up as a vendor, so use the same name that appears on your bank account and tax forms.

No federal rule requires a tax ID on a US invoice. A client that needs your taxpayer ID for Form 1099-NEC will ask for a Form W-9 instead. If you're a sole proprietor, a free EIN from the IRS keeps your Social Security number off your paperwork. The generator remembers your details and logo in your browser, so you only type them once.

2. The client's details

Bill the entity that is paying: "Maple Street Bakery LLC", not "Dana at the bakery". Add the billing address and the email address the client's accounts payable team uses, which at larger companies is often a shared inbox rather than your day-to-day contact.

If the client gave you a purchase order, put the PO number on the invoice. Many companies can't pay an invoice that doesn't match an open PO, and it waits in a queue until someone asks you for the number.

3. A unique invoice number

Each invoice needs a number that has never been used and follows on from the last one: INV-2026-0041, INV-2026-0042, INV-2026-0043. Clients quote it when they pay, which is how you match payments to invoices, and an unbroken sequence shows an auditor that no sales are missing. You don't have to start at 1. The generator suggests the next number from the last one used in your browser, and how to number invoices covers formats and what to do with canceled invoices.

4. Invoice date, due date and service date

The invoice date is the day you issue it. The due date is the day payment must arrive, and it should be printed as a date: "Due October 28, 2026" can't be misread the way "Net 30" can. If the work happened on other days, add the service date or period, for example "Work completed September 21 to 25, 2026".

Pick payment terms in the generator and it fills in the due date. The net 30 due date calculator does the same job outside the generator.

5. Line items: quantity × rate

Each line gets a description, a quantity, a unit, a rate and an amount. The amount is always quantity × rate:

• 12 hours × $65.00 = $780.00
• 3 each × $149.00 = $447.00
• 1 job × $350.00 = $350.00

Write descriptions a stranger could follow six months from now. "Website work" invites a question; "Homepage redesign: 3 layout drafts, 2 rounds of revisions" doesn't. If your hours are in a spreadsheet, copy the rows and paste them into the line items, and the generator splits them into columns.

6. Subtotal, discount and sales tax

Add the line amounts to get the subtotal. Apply any discount next, then sales tax on what's left. For a discount you give yourself, that order is standard: the Streamlined Sales and Use Tax Agreement, which many states follow, leaves seller discounts out of the taxable sales price. Use the generator's after-tax discount setting only when your state taxes the full price, as it usually does for a manufacturer's coupon that a third party reimburses.

Sales tax is set by states and local governments, not the federal government. Alaska, Delaware, Montana, New Hampshire and Oregon have no statewide sales tax, though Alaska allows local ones. Whether services are taxable varies by state, so check with your state revenue department. When some lines are taxable and others aren't, use the per-line tax toggle. If a customer gives you a resale or exemption certificate, keep a copy and leave tax off the exempt items.

7. Shipping, deposits and the balance due

Shipping goes in the shipping field or on its own line. If the client has already paid something, such as a deposit, enter it as an amount paid rather than a discount. The invoice then shows the full sale, the payment received and the balance due. A deposit entered as a discount understates the sale and, when it comes off before tax, understates the sales tax too.

8. Payment terms and how to pay

State the terms and exactly how to pay. For bank transfers, give the account name, bank, routing number and account number. For checks, say who to make them payable to and where to mail them. For cards, add a payment link. Pro prints PayPal.me, Stripe or other payment links on the invoice as text and a QR code; the money goes straight to your own account, because we don't process payments.

Tell clients that your bank details will never change by email alone, since invoice fraud often starts with a fake "we've changed banks" message. Payment terms explained covers net terms, early payment discounts and late fees.

9. Notes

Use the notes for anything that helps the invoice get paid or filed: a project reference, the late fee you agreed in the contract, warranty details or a one-line thank-you. An invoice is the wrong place to introduce terms that aren't in your contract.

10. Send a PDF and keep a copy

Send a PDF, not an editable file, to the address you confirmed in step 2, with the invoice number in the email subject. The generator names the file with the invoice number and client name. Keep your own copy: the IRS expects you to keep records that support your income until the period of limitations for that return runs out, which in most cases is three years after you file. Your browser keeps your last 50 invoices, and you can export them as a JSON file for backup.

Worked example

A furniture maker bills a restaurant for a dining set. Invoice INV-2026-0042 is dated September 28, 2026 on net 30 terms, so it's due October 28, 2026. The client paid a $1,500.00 deposit on September 1 when it placed the order, and it gets a 10% repeat-client discount. Sales tax is 8.25%.

The arithmetic:

1. Line amounts: 1 × $2,450.00 = $2,450.00; 6 × $225.00 = $1,350.00; 2.5 × $80.00 = $200.00.
2. Subtotal: $2,450.00 + $1,350.00 + $200.00 = $4,000.00.
3. Discount: 10% of $4,000.00 = $400.00, leaving $3,600.00.
4. Sales tax: 8.25% of $3,600.00 = $297.00.
5. Total: $3,600.00 + $297.00 = $3,897.00.
6. Balance due: $3,897.00 − $1,500.00 = $2,397.00.

With a percentage discount the total comes out the same in either order, but the tax line doesn't. Discounting after tax would show $330.00 of sales tax on what is really a $3,600.00 sale, $33.00 more than the $297.00 that's due. The 8.25% rate and the taxable delivery line are assumptions for this example; many states treat delivery and installation charges differently from the goods themselves.

Common mistakes

• Reusing or skipping numbers. Two invoices numbered 0042 confuse your books, and the client's accounts payable software may reject the second one as a duplicate.
• Terms without a date. "Net 30" on its own lets the client count from the day they opened your email. Print the due date.
• Billing the wrong entity. An invoice made out to a person instead of the company, or to the parent instead of the subsidiary that signed the contract, usually comes back unpaid.
• No PO number. For clients that use purchase orders, a missing PO number is a common reason an invoice sits in a queue.
• Vague descriptions. "Consulting: $6,000" invites questions, and each question adds days before payment.
• Tax on the wrong amount. Charging tax on the pre-discount subtotal, or on lines your state doesn't tax.
• Editing a sent invoice. Once the client has it, correct it with a credit note and a new invoice, not a changed version under the same number.
• Surprise late fees. A fee that wasn't in your contract or quote is hard to collect. Agree it first, then use the late fee calculator to work out the amount.

Invoicing outside the US

The steps above work anywhere, but other countries spell out what a tax invoice must show, and a missing detail can stop your client from claiming back the tax.

• United Kingdom. VAT-registered businesses issue VAT invoices that include their VAT registration number, a sequential invoice number, the time of supply, the VAT rate for each item and the total VAT in sterling. Supplies of £250 or less including VAT can use a simplified invoice. See UK VAT invoice requirements.
• Australia. GST-registered businesses issue tax invoices that include the words "tax invoice", their ABN, the issue date, a description with quantity and price, and the GST amount. Sales of $1,000 or more also need the buyer's identity or ABN. See Australian tax invoice requirements.
• Canada. What a GST/HST registrant's invoice must show steps up at $100 and $500, because those thresholds set what a business customer needs to claim input tax credits. From $100, that includes your GST/HST registration number. See Canadian GST/HST invoice requirements.

The UK, Australian and Canadian versions of the generator set the currency, date format, tax label and paper size for you.