How to Create a Professional Invoice for Free

Learn what every invoice should include, how to calculate tax and discounts, and how to create and save a clean invoice without paid software.

A clear invoice gets you paid faster and avoids back-and-forth with customers. You do not need accounting software to produce one. You need the right information, correct arithmetic and a tidy layout.

What an invoice should include

• Your details: business name, address and email.
• Customer details: who is being billed.
• Invoice number: a unique reference, such as 2026-001.
• Dates: the issue date and the payment due date.
• Line items: a description, quantity and unit price for each product or service.
• Totals: subtotal, any discount, tax and the final amount due.
• Payment instructions: how and where to pay.

Step by step

1. Open the Invoice Maker and enter your details and your customer's.
2. Add each line item. The tool multiplies quantity by unit price for you.
3. Enter a discount and tax rate if they apply to you.
4. Check the live preview, then choose Print or save as PDF.

How the totals are calculated

Subtotal is the sum of all line totals. A percentage discount is taken off the subtotal first, and tax is then applied to the discounted amount. For example: 3 hours at $50 is $150. A 10% discount ($15) gives $135, and 8% tax ($10.80) gives a total of $145.80.

Tax rules differ by country and by type of business, so confirm the correct rate and wording with your tax authority or accountant.

Common mistakes

• Reusing an invoice number.
• Leaving out payment terms or a due date.
• Applying tax before the discount when your rules require the opposite order.
• Sending without proofreading names, amounts and dates.

Always review the finished invoice before you send it.