Invoice Generator: Numbering, Tax Lines and Terms That Get You Paid
This tool generates invoices with the fields, numbering discipline and tax handling that accounting software and your clients' finance departments expect. A complete invoice requires: your legal business name and address, the client's legal name and address, a unique invoice number, issue date, due date, an itemised list of goods or services with quantities and unit prices, the applicable tax treatment per line, and the total payable with payment instructions.
Numbering discipline. Numbers must be unique and sequential, with no gaps you cannot explain: `INV-2026-001`, `INV-2026-002`, and so on. Never reuse a number, and never delete an issued invoice — if one is wrong, void it and issue a credit note referencing the original number. Auditors and tax authorities read gaps in a sequence as missing revenue.
Tax and VAT line handling. Tax is shown as its own line after the subtotal, never folded silently into prices unless your jurisdiction requires tax-inclusive display. Apply the rate per line when items are taxed differently. Cross-border B2B services are commonly zero-rated or reverse-charged; domestic consumer sales commonly carry VAT. The rates below are illustrative — use the rate your jurisdiction mandates for your supply.
Worked example.
| Line | Calculation | Amount |
| :--- | :--- | :--- |
| Consulting, 10 hrs × $150 | 10 × $150 | $1,500.00 |
| Design work, fixed fee | — | $800.00 |
| Subtotal | $1,500 + $800 | $2,300.00 |
| VAT @ 20% (illustrative domestic sale) | $2,300 × 0.20 | $460.00 |
| Total due, domestic | $2,300 + $460 | $2,760.00 |
| Total due, zero-rated export sale | $2,300 × 0% tax | $2,300.00 |
Payment terms. State them on the invoice itself: "Net 14 — due 14 days from issue date," plus accepted methods and any late-payment fee your contract permits. Vague terms are the most common cause of slow payment our editorial analysis encounters.
Limitations — when not to rely on this. The generator produces the document; it does not determine your tax obligations. Whether VAT applies, at what rate, and whether reverse-charge rules govern a cross-border sale depends on both jurisdictions involved — confirm with an accountant before your first invoice in a new market.
> [!TIP]
> Put the due date in words ("Due 14 March 2026"), not only as "Net 14." Clients pay against dates, not against terms they have to calculate.