How to Invoice a Client (and Actually Get Paid on Time)

Published June 26, 2026

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A finished project doesn’t pay you. The invoice does — and yet invoicing is the step most freelancers wing. They finish the work, fire off a vague “here’s what you owe me” email, and then spend the next two months wondering why they haven’t been paid. A clear, professional invoice sent at the right time is the difference between getting paid in a week and chasing money for a quarter. Here’s how to do it properly.

What an invoice actually is

An invoice is two things at once: a formal request for payment, and a record — for you and the client — of what was delivered and what’s owed. Both jobs matter. As a request, it needs to be clear and easy to act on so the client can approve and pay it without coming back with questions. As a record, it needs the details you’ll want later for your bookkeeping and taxes.

A casual “you owe me £400” message fails at both. It’s easy to ignore, easy to dispute, and useless when you’re reconciling your income at tax time.

What every invoice must include

You don’t need fancy software, but you do need every one of these fields. Leaving one out is how invoices get “stuck in accounts” for weeks:

• The word “Invoice” and a unique invoice number (e.g. 2026-001, 2026-002). Sequential numbers keep your records clean and let both sides reference a specific bill.
• The date issued and the date payment is due — an actual date, not “in two weeks.”
• Your details — name or business name, and how to reach you.
• The client’s details — the name and, ideally, the specific person or department that approves payment.
• An itemised list of what you’re charging for: a line per deliverable or work period, with a short description and the amount. “Web design — £600” invites questions; “Homepage design and build (per agreed proposal) — £600” does not.
• The total owed, and tax if you charge it, shown clearly.
• Payment instructions — exactly how to pay (bank details, payment link, etc.) and any reference to include.
• A reference to the project, contract, or the client’s purchase-order number if they use one.

Address the invoice to the person or system that actually pays. With bigger clients, the person who hired you often isn’t the one who cuts the cheque — ask early who invoices should go to.

Setting payment terms (so “when” is never a question)

“Payment terms” just means how long the client has to pay. The common options:

• Due on receipt — payable immediately. Best for small jobs and new clients.
• Net 7 / Net 14 — due within 7 or 14 days. A sensible default for solo work.
• Net 30 — due within 30 days. Standard for larger companies; only offer it if you have to, because it’s a month of your money sitting elsewhere.

Two rules make terms work. First, agree them before the work starts — your freelance contract should state the payment terms so the invoice only confirms what’s already agreed. Second, put the exact due date on the invoice, not just “Net 14.” A specific date — “Due: 10 July 2026” — is far harder to drift past than a term the client has to calculate.

Take a deposit — don’t invoice everything at the end

The single biggest invoicing mistake is leaving 100% of the fee until the work is done. Instead:

• Project work: invoice a deposit before you start (a portion of the fee), and the balance on delivery.
• Larger projects: split into milestone invoices — for example, a third up front, a third at the midpoint, a third on completion.
• Ongoing/retainer work: invoice on a fixed schedule (e.g. the 1st of each month), in advance where you can.

A deposit means you’re never fully exposed, and it quietly filters out clients who were never serious. It also reframes payment as normal and expected rather than something you’re nervously asking for at the end. (This is the same logic that protects you on pricing and scope.)

How to actually send it

• Send promptly. Invoice the moment a milestone is reached — on delivery, or on your set date. A delayed invoice means a delayed payment, and a stale one is easy for a client to push down the pile.
• Send a PDF, not an editable document. It looks professional and can’t be accidentally altered.
• Write a short, warm covering message: thank them, note that the deliverable is attached/delivered, and that the invoice is attached and due on [date]. Keep it human and brief.
• Make it effortless to pay. Include a payment link or clear bank details directly on the invoice. The fewer steps between “I should pay this” and “paid,” the faster you get the money. (See how to take payments online for the options that suit service work.)
• Keep a copy of every invoice you send, filed by number.

When a client doesn’t pay: the polite escalation ladder

Most late invoices aren’t malice — they’re forgotten, lost in a busy inbox, or stuck behind someone’s approval. So start gently and escalate only as needed. Keep everything in writing.

1. A day or two after the due date — a short, friendly nudge that assumes an oversight: “Hi [name], just checking this one didn’t slip through — invoice #2026-014 was due on [date]. Let me know if you need anything from me to process it.” No accusation; you’re making it easy to fix.
2. About a week later, no response — follow up more firmly. Restate the invoice number, amount, and original due date, and ask for a specific payment date. Re-attach the invoice.
3. Still nothing — refer to your contract’s late terms. This is exactly why your agreement should state when a late fee applies and when work pauses. If you have ongoing work for them, it’s reasonable to pause it until the outstanding invoice is cleared.
4. Persistent non-payment of a meaningful amount — send a final written request making clear it’s the last reminder before further steps, then consider a formal demand letter or your local small-claims process. For larger sums this is worth it; for tiny ones, weigh the time against the amount.

Through all of it, stay calm and professional. The freelancer who chases politely and persistently gets paid; the one who either says nothing or explodes usually doesn’t. If a client is repeatedly difficult about money, treat that as data — see dealing with difficult clients and think hard before taking the next job.

Common mistakes

• No deposit. Doing the whole job before any money changes hands is how freelancers get stiffed.
• Vague line items. “Consulting — £500” invites “for what?”; a clear description doesn’t.
• No due date. “Net 30” without an actual date drifts; a specific date anchors it.
• Sending late. Every day you delay the invoice is a day added to when you get paid.
• No invoice number or copy kept. It makes chasing payment and doing your taxes painful later.
• Going silent on a late invoice. Unpaid invoices rarely fix themselves — a polite reminder almost always works, but only if you send it.

A faster way to create them

You can build invoices in a document template, but it’s fiddly to keep numbering and totals straight. A simple generator handles the layout, the maths, and a clean PDF for you — I built a free freelance invoice generator for exactly this: fill in the line items, set the due date, and download a tidy, professional invoice. No signup, nothing to install.

The honest bottom line

Invoicing isn’t admin you tolerate — it’s the part of freelancing that actually gets you paid, so it’s worth doing well. Send a clear, itemised, numbered invoice promptly; state an exact due date you agreed up front; take a deposit so you’re never fully exposed; make paying effortless; and if it goes late, chase politely and persistently in writing. Do that consistently and “waiting to get paid” stops being a normal part of your month.

Skip the blank page: my Freelancer’s Client Toolkit includes ready-to-use invoice and polite payment-follow-up templates alongside the proposal, agreement, and onboarding ones.

Keep reading

• How to write a simple freelance contract
• How to price your freelance services
• How to take payments online