Freelancers lose more money to slow invoicing than to bad clients. The client was happy, the work was approved, and then the invoice went out two weeks later with "net 30" on it, so the money arrived six weeks after the job. That gap is where cash-flow stress lives.
This guide is the version I wish someone had sent me when I started talking to freelancers about money: what goes on the invoice, when to send it, and what to do when the due date passes.
What a freelance invoice must contain
Most countries agree on the basics. If one of these is missing, an accountant on the client side can legally bounce the invoice back to you, and you start the clock again.
| Field | Why it matters |
|---|---|
| Your full name or business name, address, email | The client's bookkeeper files it under you |
| Your tax ID (VAT number, EIN, IČO, UTR) | Required for VAT invoices in the EU and UK; US clients ask for it on the W-9 |
| Client's legal name and address | "Acme" is not enough, "Acme Studio Ltd, 12 Rue X, Paris" is |
| Invoice number, unique and sequential | Tax offices check for gaps. 2026-001, 2026-002, never reused |
| Invoice date and due date | The due date as a real date: "Due 24 October 2026" |
| Line items: description, quantity, unit, rate, amount | "Design, 6.5 h × $75" beats "Design work" |
| Subtotal, tax if any, total, currency | Say the currency, "USD 487.50", especially across borders |
| How to pay | IBAN + BIC, or account and routing number, or a card link |
| Payment terms and late fee, if you use one | One line, same on every invoice |
Two things people often leave out: the currency (a Czech freelancer invoicing a US client in "$" has caused more than one wrong transfer) and the client's legal name, which is the one thing a finance department cannot fix for you.
VAT and sales tax, briefly
If you are VAT registered in the EU and invoice a business in another EU country, you usually charge 0 % and write "Reverse charge" on the invoice, with both VAT numbers on it. Invoicing a private person, or a client in your own country, means your normal rate applies. US freelancers mostly do not charge sales tax on services, but it varies by state. When unsure, ask an accountant once and then put the answer into your invoice template so you never think about it again.
When to send the invoice
The single biggest lever is timing. Three options, from best to worst:
- On approval. The client says "looks great", you send the invoice within the hour. The work is fresh, the goodwill is at its peak, and the person who approved it is the person who forwards it to finance.
- On a fixed day each month, for retainers and ongoing work. Same day every month, same format, so the client's bookkeeper expects it.
- At month end for everything. Common, and the worst. The invoice lands when every other supplier's invoice lands, and your three-day job from the 2nd is paid on the 30th of next month.
For projects over about two weeks, split it: 30 to 50 % up front, the rest on delivery. A client who will not pay a deposit is telling you something.
Payment terms that work
"Net 30" is a habit from a time when invoices were posted and cheques were mailed. For a solo freelancer it means waiting a month for money you already earned.
- Due in 7 days is normal for freelancers in most of Europe and the US. Few clients push back.
- Due in 14 days if the client is a larger company with a payment run (ask: "When is your payment run?" and set the due date two days before it).
- Due on receipt for small amounts and first-time clients.
Write it as a date. "Due 24 October 2026" gets paid sooner than "Net 14" because nobody has to count.
A late fee is optional. If you use one, keep it boring and legal in your country (the EU statutory rate is the ECB rate plus 8 points; many freelancers simply write "1.5 % per month on overdue amounts"). The fee rarely gets collected. Its job is to make the invoice look like it came from someone who follows up.
The reminder rhythm
Here is the part most guides skip, and the part that actually gets you paid. Late invoices are almost never a client refusing to pay. They are an email that got buried. So remind, politely, on a schedule:
| When | What to send |
|---|---|
| 3 days before due | Optional, only for invoices over your "this would hurt" threshold. "Heads up, invoice 2026-014 is due on Friday." |
| Due date | "Invoice 2026-014 was due today. Could you check whether it went out?" |
| 3 days after | Same message, shorter, with the PDF attached again. |
| 10 days after | Ask directly: "Is there an issue with the invoice, or a date I can expect payment?" |
| 21 days after | Phone call or a message to the person who approved the work, not accounting. |
Keep the tone the same from the first reminder to the last: friendly, short, factual. Attach the invoice every time so nobody has to search for it. If you do this by hand, put the dates in your calendar the moment you send the invoice. This is the exact rhythm Go Lancer runs automatically, with the reminders sent in your name, so I know it works: most invoices get paid after the first or second nudge.
A plain invoice email
The invoice is the PDF. The email just needs to get it opened.
Subject: Invoice 2026-014 from Jana Novak, due 24 Oct
Hi Tom,
Attached is the invoice for the September landing page work (6.5 h).
Total USD 487.50, due 24 October. Bank details are on the invoice.
Thanks again for the quick feedback on the revisions.
JanaNo "I hope this email finds you well", no paragraph about the weather. Subject line with the number, the sender, and the due date, so it can be found later.
Mistakes that cost freelancers money
- Vague line items. "Consulting" invites questions. "Kick-off call 1 h, wireframes 4 h, revisions 1.5 h" gets approved.
- Sending it to the wrong person. Ask on day one: "Who should invoices go to?" Then CC your contact.
- No invoice number sequence. Reusing numbers or skipping them makes your invoices look unreliable to an auditor, and your own records a mess.
- Waiting to invoice until you have "enough". Invoice every piece of approved work. Small invoices get paid faster than large ones.
- Not tracking what is unbilled. Hours you logged but never invoiced are the most common silent loss. Check your unbilled total every Friday.
FAQ
Should I invoice in my currency or the client's?
Invoice in the currency you agreed the price in. If the client is in the US and you quoted in USD, invoice in USD and let your bank convert. Mixing currencies on one invoice is where mistakes happen. Note the currency in words or ISO code (USD, EUR, CZK), not just a symbol.
Can I charge a late fee if it was not on the invoice?
Usually no. The late fee has to be in your terms or on the invoice before it is due. Put one line on every invoice and in your quote, and you are covered.
What if the client says the invoice never arrived?
Resend it the same day, to the original address plus any accounts-payable address they give you, and ask them to confirm receipt. Then move the due date only if the first one was clearly your mistake. "Never arrived" after the due date is the most common delaying line; being friendly and immediate is the answer.
Do I need an invoicing tool, or is a template enough?
A template is enough for your first few clients. The moment you have more than three open invoices at a time, you need something that tracks what is paid, what is overdue, and reminds the client for you. That can be a spreadsheet with a calendar, or an app. The tool matters less than the rhythm.
Full disclosure: I've never been a freelancer. I'm a neuroscience grad who fell in love with product and with talking to customers. I ran 100+ interviews with freelancers before writing a line of code. Go Lancer is what came out of those conversations.