In order for an invoice to be a valid sales document, it must have an invoice number. However, there are rules about what that number can be.
The first time you create an invoice, you can start with any number you want, but after that you must continue with the next number in the sequence. There also can’t be any gaps in the sequence. If you start with 1001, for example, the next number must be 1002, 1003 and so on.
An invoice number is important
The reason you need a unique invoice number is for tracking purposes. It should be possible for an accountant, auditor, the tax authorities, or other third parties to review the complete set of invoices you’ve sent out. With invoice numbers, they can be sure that they’ve got everything.
If you switch to another invoicing software, the first invoice in the new software should continue the number sequence: If the last invoice you sent had the number 1089, you should start with number 1090 in the new system.
Because the number sequence must be unbroken, you can’t delete an invoice or change it after it’s been issued. If you’ve sent an invoice with errors to your client, you have to create what’s called a credit note to annul the invoice.
How to make an invoice
Usually, the invoice number must be either automatically generated by invoicing software or pre-printed on invoice pads in order to be valid.
Whether you’re allowed to create an invoice in Word or Excel or use an online invoice generator, depends on what country you’re operating in. You should check what applies to you.
Generally, we recommend using invoicing software because you can be sure that you’re following the rules and regulations, and you’ll be able to create professional invoices much quicker than if you use templates or generators. You can also rest easily knowing that your invoices are stored safely.
If an invoice isn’t paid by the due date, you’ll be notified so that you can follow up with the client and get paid.