How-to guide · Invoicing

What to include on a freelance invoice: the complete checklist

By the WorkKitly Team · Last updated: November 2026 · 6 min read

A freelance invoice needs fifteen things: your name and contact details, the client's correct name, a unique invoice number, the issue date and a real due date, an itemised list of the work with quantities and rates, the subtotal, any tax shown separately, the total due, the currency, how to pay, and the terms you agreed — plus a purchase-order reference and your tax ID where they apply. Leave one out and the invoice usually still gets paid eventually, but eventually is the expensive word: most late payments begin as an invoice an accounts team could not process without asking you a question. This checklist goes field by field — what to write, why it matters, and the mistake that most often sends the invoice back.

The checklist: every field, in the order it appears

Work down this list before you send. It takes a minute once the habit forms, and every row exists because its absence has delayed somebody's payment.

Field	Why it matters	The common mistake
Your name or business name, with contact details	Identifies who is owed the money, and where questions should go.	Billing under a name that does not match your bank account or registration.
The client's correct legal name and address	Accounts teams pay the entity in their records, and the right name reaches the right approver.	Naming the friendly contact who briefed you instead of the company that actually pays.
A unique invoice number	The reference both sides use in every email and record — how an invoice is found again.	Restarting at #001 per client, or reusing a number.
The issue date	Fixes the invoice in your records and starts the payment clock.	Leaving it off — or backdating it to when the work finished, weeks earlier.
The due date, as an actual calendar date	"Due 17 November" cannot be misread, and tells the payment run which batch it belongs in.	Writing only "Net 30" and leaving the client to guess when the clock started.
An itemised description of the work	The approver matches each line against what was agreed and delivered; vague lines get questioned.	One line — "Design work: $1,080" — that the client cannot check.
Quantities and rates for each line	Shows the arithmetic behind each line: hours × rate, days × day rate.	Line totals only, with nothing to reconcile against your quote.
A subtotal	The pre-tax sum the client checks against the agreed price.	Jumping straight to the total, hiding where a mismatch came from.
Tax, shown separately, where it applies	Where VAT, GST or sales tax applies, clients commonly need it itemised to process the invoice and handle their own tax.	Hiding tax inside prices — or charging it when you are not registered to collect it.
The total amount due	The single figure the client pays — and the most prominent number on the page.	A total that does not equal the lines plus tax. Even a small slip sends it back with a query.
The currency	Cross-border clients otherwise guess or convert at their own rate.	A bare "$" or unlabelled number on an invoice sent abroad.
How to pay: bank details or a payment link	Removes the last excuse for delay — it can be paid the moment it is approved, without another email.	Writing "bank transfer please" with no details — or details that changed since last time.
Payment terms — and the late-fee term, if one was agreed	Restating agreed terms makes them easy to point to later, politely, if the date passes.	Introducing a late fee for the first time on the invoice itself — unagreed, it starts an argument, not a payment.
The client's purchase order or reference number, if they use one	Many accounts systems cannot enter an invoice without its PO.	Assuming a big client works like a small one. Ask before invoicing, not after it bounces back.
Your tax or VAT ID, where applicable	Commonly expected in many countries; it lets the client verify you and handle their own tax.	Leaving it off where expected — or printing one before you have it.

You do not have to assemble this by hand. WorkKitly's free invoice generator is built around exactly this list — number, dates, itemised lines, tax, totals, currency, payment details, and a notes field for references like a PO number — and it builds the invoice in your browser, with no sign-up and nothing uploaded.

Country notes: what is commonly expected in the US, UK, EU and Canada

The checklist travels well, but the emphasis shifts by country. What follows is what clients in each place commonly require or expect — everyday practice, not a legal summary.

United States. There is no single standard format, so clarity does the work: both parties named, itemised charges, a clear total. Clients commonly ask for your tax ID or a W-9 form for their records, especially before a first payment, and larger clients often work through purchase orders — if a PO exists, its number belongs on the invoice.

United Kingdom. If you are VAT-registered, clients commonly expect a VAT invoice: your VAT number, the date, and the VAT rate and amount shown separately for each rate. If you are not VAT-registered, you simply do not charge VAT — the invoice looks the same minus the VAT lines, and adding them anyway causes real confusion. The invoice generator for UK freelancers starts in pounds and explains the VAT side as you go.

European Union. Business invoices commonly carry sequential numbering, supply and issue dates, and both parties' names and addresses. For cross-border business-to-business work, both VAT IDs commonly appear, since the client's accounting depends on them.

Canada. If you are registered for GST/HST, invoices commonly show your GST/HST number with the tax as its own line, so the client can claim their input tax credits; unregistered small suppliers charge no tax at all. The invoice generator for Canadian freelancers starts in Canadian dollars and covers the registration threshold in plain language.

The honest caveat: rules vary by country, registration status and client — and they change. Treat this as a practical checklist, not tax or legal advice: check your local requirements once, or ask an accountant once, then reuse the answer in your template for good.

A filled-in example

Here is the checklist with every field completed — a fictional example, a designer billing a company client, with invented names and details:

Invoice number	2026-041
Issued	3 November 2026
Due	17 November 2026
From	Sam Carter, Carter Creative Studio · sam@cartercreative.example
Billed to	Northwind Traders Ltd · Accounts Payable
Client reference	PO-8841
Work	Homepage redesign — 2 days × $450/day = $900
Work	Landing page copy edits — 3 pages × $60/page = $180
Subtotal	$1,080
Tax	None applied in this example
Total due	$1,080 USD
How to pay	Bank transfer — account ending 1234 (fictional details)
Terms	Payable by the due date above. A late fee of 1.5% per month applies, as agreed in the signed proposal of 20 October 2026.

Nothing on it is decorative: every row identifies the payment, lets the client check it against what was agreed, or tells them how to complete it.

Mistakes that delay payment

Sending it late. The payment clock starts when the invoice lands in the client's system, not when the work finished. An invoice sent a week after delivery adds a week to your own wait — invoice the day the work is signed off.

Sending it to the wrong inbox. The person who briefed you often is not who approves or pays. Ask who needs it — approver, accounts address, or both — and send it there first time, not after a fortnight of silence.

Numbers that do not reconcile. If the total disagrees with the lines, or the lines with the quote, the invoice gets queried — and a query usually resets the payment clock to zero. Add it up once more before sending.

Terms nobody agreed. A late fee, shorter due date or currency change introduced for the first time on the invoice is not a term but a negotiation — and negotiations pause payments. Agree terms in the proposal, then restate them.

Firing and forgetting. Note the due date when you send the invoice and chase promptly when it passes — a polite reminder a few days later is normal business practice, not rudeness. Our late payment email generator has the wording for each stage, from gentle reminder to final notice.

Questions

What has to be on a freelance invoice by law?+

There is no single worldwide answer, and anyone who gives you one is guessing. The fields that are commonly required or expected in most places are the ones on the checklist above: both parties identified, a unique number, dates, an itemised description, the totals, and tax details where they apply. What your country, your registration status and your client's accounts team require can differ — check your local rules once, then keep the answer in your template.

Can I write 'net 30' instead of a due date?+

You can, and many freelancers do — but print the actual date beside it. 'Net 30' leaves the client to work out when the thirty days started; a printed due date cannot be argued with, and it is the date you will point to if you have to chase. It costs four words.

Should I add tax to my invoice if I am not registered for it?+

Only charge and show tax you are registered or required to collect — adding VAT, GST or sales tax because the template has a box for it creates a liability from nothing and confuses the client's accounts team. If you are registered, show tax as its own line with your tax ID. Unsure which side of the line you are on? That is a one-time question for an accountant, not a guess to repeat on every invoice.

I sent an invoice without the client's PO number. What now?+

Send a corrected copy promptly — same invoice number, the missing reference added, and a one-line note saying it replaces the earlier copy. Do not wait for the client to discover the problem at payment time: an invoice their system cannot process sits in a queue nobody owns. A quick correction restarts the clock; silence lets it run out.

Related: put the checklist to work

The amounts on your lines should come from a rate you have worked out, not one inherited from your last job — the freelance hourly rate calculator builds that rate from your income, costs and real billable hours. Then build the invoice itself with the free invoice generator: every field on this checklist is already on it. Send it the day the work lands, note the due date — and if that date still passes unpaid, you know where the chase wording lives.