Accounting Guides
Practical guides on accounting for freelancers and small businesses.
How to Number Invoices (and Why It Matters)
Sequential invoice numbering keeps your books traceable and your clients organized. Learn simple numbering systems and what to avoid.
Read guide ›How to Calculate an Invoice Total
Subtotal, discounts, tax, total due: calculate an invoice correctly every time with this step-by-step method and example.
Read guide ›What you'll find in the accounting guides
The guides on this page are written for freelancers and small businesses who have to handle their own books. Each one walks through a single practical task instead of theory: how to number invoices so your records stay traceable, and how to calculate an invoice total from subtotal through discounts and tax to the amount due. Both guides are short, use plain language, and give a step-by-step method you can apply to the invoice in front of you. When you are ready to produce the document itself, create it with the free invoice generator — fill a form and download an A4-accurate PDF, with no sign-up and no watermark.
Numbering and totals: why both matter
Sequential invoice numbering keeps your books traceable and your clients organised; it is the thread that lets you and your accountant find any invoice later. Getting the total right matters for the same reason — subtotal, discounts, tax and total due each have a place on the page, and mixing them up makes an invoice hard to reconcile. These are the two things that cause the most avoidable back-and-forth with clients, which is why they sit at the top of this guide collection. If you would rather start from a ready layout, download a free invoice template.
Where the guides fit in your workflow
Accounting work rarely stops at sending the invoice. Once a document is numbered and totalled correctly, the next steps are keeping track of what happens to it. You can track which invoices are paid, due or overdue, and set up automated reminders and follow-ups for unpaid invoices. For work you quote before you bill, the free estimate generator covers estimates and quotes. If you are new to all of this, the step-by-step guide to creating an invoice and the guide to invoicing for freelancers are good starting points.
Frequently asked questions
Do I need accounting software to use these guides?
No. The guides describe methods you can apply by hand to your own invoices, whether you keep records in a spreadsheet, on paper or in software.
Are the guides free to read?
Yes. Every guide on this page is free to read, and Invoala's invoice generator is free to use — no sign-up and no watermark on your PDF.
What format are the invoices I create?
Invoala produces an A4-accurate PDF that you download after filling in a form.
Which guide should I read first?
If you are just starting out, read How to Number Invoices first, then How to Calculate an Invoice Total. Numbering is what makes later tracking and reminders possible.
Can I keep reading guides after this page?
Yes — more guides are listed on this page, and you can head back to the full guides index at any time.