Fill your business details once, then add a line for each thing you are billing: a description, a quantity and a rate. The invoice number, issue date and due date go at the top; the tax rate and any flat discount go below the totals. The preview updates as you type, and the print button produces a clean page you can save as a PDF.
Number invoices in one unbroken series and never reuse a number, even for a cancelled job. A client's bookkeeper matches payments to numbers, and a gap or a duplicate turns a simple payment into a phone call.
A three-line invoice for a small web job, with a 6% tax rate and a $50 goodwill discount:
| Line | Amount |
|---|---|
| Landing page build (1 × $1,200) | $1,200.00 |
| Copywriting (4 hours × $85) | $340.00 |
| Hosting setup (1 × $150) | $150.00 |
| Subtotal | $1,690.00 |
| Discount | −$50.00 |
| Tax at 6% on $1,640 | $98.40 |
| Total due | $1,738.40 |
Net 30 from an issue date of 2 November 2026 puts the due date at 2 December 2026, which is a Wednesday, so the payment can actually be sent that day rather than sitting until the following Monday.
The total is the number the client pays; the subtotal is the number you can defend line by line. Keep both visible. A client who queries a total can be walked through the lines, and a client who queries a line can see how it rolls up.
Where tax goes is the detail that causes reissues. Sales tax applies to goods in most US states and to a narrower set of services, and the rules differ by state and by whether the client is a business reselling your work. The tax field here is straightforward arithmetic: whatever rate you enter is applied to the discounted subtotal. It does not decide whether you should be charging tax at all, and it does not handle a mixed invoice where some lines are taxable and some are not. If your work spans those categories, split it into two invoices or add the tax as its own line rather than trusting the rate box.
Discounts belong before tax, because a discount reduces the taxable amount. Applying a discount after tax overcharges the client by the tax on the discount and creates a mismatch with your own records.
Net 30 is the default in most business-to-business work, Net 15 for smaller clients. Put the terms in words on the invoice itself: "Due 2 December 2026" is unambiguous in a way that "Net 30" is not.
It depends on your state, your service, and your client. The invoice calculates the rate you give it; it cannot tell you whether that rate is right. Check with your state's revenue department.
Whichever you agreed to. If you quoted a flat fee, listing hours invites the client to reprice the work; if you bill hourly, listing the hours is the whole point.
Your name and contact details, a unique number, the issue and due dates, an itemised description, the total, and how to pay. Missing payment instructions is the most common reason an invoice sits unpaid.
Yes, but leave the tax box at zero unless you know the rule. Cross-border services usually follow the client's jurisdiction, and that is a question for an accountant rather than a calculator.
The totals are arithmetic. Whether the document is enough for your taxes is a recordkeeping question.
Last updated: November 2, 2026. Reviewed by David Liu.