Invoice generator

What has to be on it

An invoice is a request for payment, and the things that make it work are unglamorous: who is billing, who is being billed, what for, how much, and how to pay. Most invoices that get queried are missing the last one.

• Your business name and contact details, and any license or tax number you normally show
• The customer's name and address, spelled the way they spell it
• A unique invoice number — sequential is fine, but never reuse one
• The date issued and the date payment is due, as actual dates rather than 'net 30'
• Each line described in words the customer will recognize from the job
• How to pay: bank details, or whatever method you accept

The things that get you paid sooner

Send it the day the work finishes. An invoice that arrives three weeks later signals that you are not in a hurry, and it gets treated accordingly.

Put a real date on it rather than a payment term. 'Due 15 March' is harder to lose track of than 'net 14', and it removes the argument about when the clock started.

Describe the work the way the customer experienced it. A line reading 'labor, 4 hours' invites a question. 'Replace hot water heater and reroute overflow — 4 hours' does not.

The arithmetic is done properly

Every figure here is calculated in whole cents rather than with decimal fractions, so the line items always add up to the total. That sounds like a low bar, and it is one that a surprising amount of software fails to clear.

This tool also deliberately does not use AI. Language models are unreliable at arithmetic, and an invoice that does not reconcile is worse than no invoice at all.

What this is not

It creates a document. It does not track whether the invoice was paid, chase it, file it, or work out what tax you owe — the tax rate is whatever you enter, and getting that right is between you and your accountant.

If an invoice goes unpaid, the payment reminder generator writes the follow-ups.