Invoice & freelance finance guides
17 guides on the financial side of freelance and small-studio work: what to put on a document, what to charge, what to leave off, and what to do when the money does not arrive. Every one is paired with the tool that does the arithmetic, so you can check the numbers rather than take them on trust.
Last reviewed 17 Sep 2026.
Invoices
Creating, sending and correcting the documents you bill with.
How to Create an Invoice: Step by Step
Eight steps from blank page to paid, with the two mistakes that cost the most time.
Pairs with the document generator
What an Invoice Must Contain
The mandatory fields, the tax numbers, and the payment terms that belong on the page.
Pairs with the document generator
Invoice Numbering: Best Practices
Sequential schemes, year-based formats, and why gaps and duplicates cause real work later.
Pairs with the document generator
Invoice vs Quote vs Receipt vs Credit Note
Six document types, what each one is for, and the mistakes that come from using the wrong one.
Pairs with the document generator
How to Turn a Quote Into an Invoice
What to change, what to leave alone, and the deposit cases that catch people out.
Pairs with the document generator
How to Issue a Credit Note
Corrections that have to become a new document, and how to make one that allocates cleanly.
Pairs with the document generator
Taxes
Working out what to charge, and what to leave off the invoice.
Tax Exclusive vs Tax Inclusive
The division mistake almost everyone makes, and the correct way round both calculations.
Pairs with the Sales Tax, VAT & GST Calculator
VAT vs GST vs Sales Tax
Same arithmetic, different law: how the three regimes differ in practice.
Pairs with the Sales Tax, VAT & GST Calculator
Charging Tax to Overseas Clients
Place of supply, reverse charge, and when the honest answer is to charge nothing at all.
Pairs with the Sales Tax, VAT & GST Calculator
Profit & pricing
Setting prices so the business survives the work.
Profit Margin vs Markup
The two numbers that are not interchangeable, and how to price from the one you want.
Pairs with the Profit Margin Calculator
How to Price a Project
A defensible pricing method, and why the fee for waiting has to be in the number.
Pairs with the Profit Margin Calculator
Gross Margin vs Net Margin
Which margin to quote to a client, and which one to look at yourself.
Pairs with the Profit Margin Calculator
Payments
Getting paid on the date you agreed, and what to do when you are not.
Payment Terms That Get Paid Faster
Short practical changes to payment terms that move the payment date earlier.
Pairs with the Late Payment Fee Estimator
Late Payment Interest Explained
How interest is calculated, what your contract should say, and what it costs to enforce.
Pairs with the Late Payment Fee Estimator
Following Up on Unpaid Invoices
The escalation ladder, the wording at each rung, and the point where chasing stops being worth it.
Pairs with the Late Payment Fee Estimator
Freelancing
The admin around the work: contracts, records, and cash flow.
The tools these guides refer to
Each guide names the tool it belongs with. Open it in a second tab and work through the numbers as you read.
- 01
Invoice Generator
Fill in the form, upload your logo, and download a clean vector PDF invoice. Drafts save automatically in your browser.
- 02
Profit Margin Calculator
Turn cost and revenue into gross margin, markup, net profit and net margin so you can price a project before you quote it.
- 03
Sales Tax, VAT & GST Calculator
Add tax on top of a net price, or work backwards from a tax-inclusive total. Preset rates for 5%, 10%, 18% and 20%.
- 04
Late Payment Fee Estimator
Compare daily simple interest against daily compound interest on an overdue invoice, with a grace period and optional flat fee.
Not sure which document you are sending? Compare the six document types.