Why the tax line belongs on the invoice
Most invoicing tools end at the total, and the total is the least useful number on the page for a self-employed person. The moment that matters is not "what did I bill" but "what do I actually keep once the taxman has taken his share" — and if you only answer that question in April, you will already have spent the money. This freelance invoice generator puts three numbers side by side: the amount due from your client, the slice you set aside for tax, and your take-home. On the defaults (40 hours at 75) that reads 3,000.00 due, 900.00 set aside, 2,100.00 yours. You can copy the formatted invoice straight into an email, and the set-aside figure is already sitting in front of you while the payment is still a promise.
The 30% default is not arbitrary. Self-employment tax alone is 15.3% — 12.4% Social Security plus 2.9% Medicare — applied to your net earnings from self-employment, as the IRS self-employment tax rules explain. On top of that sits federal income tax at your marginal bracket (10% to 24% covers most freelancers), and state income tax where it applies. Stack the two and a realistic default lands between 25% and 35% of every dollar you bill — so 30% is the honest middle. It is an estimate, not a rule: if you are in a high bracket, carry state tax, or owe the additional Medicare tax, nudge the field up; if you are low-income or in a no-income-tax state, nudge it down. Run your own percentage through the freelance tax calculator — the same tool freelancers use as a self employment tax calculator and a 1099 tax calculator — and confirm the result with your accountant. This page is education, not tax advice.
Payment terms: put Net 15 on it
An invoice without a due date is a suggestion. Net 15 — payment due 15 days from the invoice date — is the sane default for a solo operator: it is long enough that a finance team can process it, short enough that you are not financing your client for a month. Write the terms on the document itself: issue date, due date, accepted payment methods, and your bank or payment details. Then add one sentence about what happens if the date passes — a late fee or interest clause you can enforce. When the date does slip, the late payment interest calculator works out the interest and compensation owed on the overdue balance in your jurisdiction, so the follow-up email carries a number instead of a request.
What every invoice must include
The set-aside line is an addition, not a substitute for the basics. Every invoice you send needs your legal name and contact details and your client's, a unique invoice number, the issue date and due date, a clear description of the work with hours and rate, a subtotal, any tax lines that apply, the total with its currency, and your payment instructions. The requirements differ by country — VAT registration numbers, reverse-charge wording for cross-border business, withholding lines in some markets — and the full country-by-country checklist lives in the freelancer invoicing rules guide. Miss a required field and payment queues in a client's accounts-payable system; add the set-aside line and you get paid the same day with the right amount still in the bank.
Free vs paid invoice generators
A free generator is fine while invoice volume is low and clients pay on time: you type the numbers, copy the text, and move the tax slice yourself. Once late payers multiply and chasing eats whole afternoons, paid tools earn their keep through automatic reminders and reports showing who owes what — not through prettier templates. Upgrade when admin hours, not invoice count, become the real cost.
Every figure above is hand-checked: the worked example was recomputed independently of the calculator code, and tax figures track 2026 IRS limits. How we check every page.
Related tools
Pair this with the invoice generator guide — anatomy, payment terms, and a copy-paste template — and these three tools: the late payment calculator for overdue invoices, the tax set-aside calculator for your real percentage, and the hourly rate calculator for the number you put in the rate field. Free to use, no account, no upload — your figures never leave the browser.