How to Set Up a Simple Invoice System That Actually Gets You Paid

Late payment is rarely about the invoice. It is about what happens before you send it and what happens when it is ignored. Here is a system for both.

Published 2026-08-17 · 4 min read

Most advice about late payment focuses on the invoice document. Use a template, add your payment terms, include your bank details.

That is worth doing and it is not where the problem is. Invoices get paid late because of what happened before they were sent, and because nothing happens after they are ignored. This article deals with all three stages.

Before the work: what makes an invoice payable

The invoice is the last step. Most late payment is decided earlier.

Agree the amount in writing before starting. Not a conversation, not a rough figure — something written, even an email saying "confirming: four hundred for the work discussed, payable within fourteen days of completion." If the amount is disputed at invoice stage, you have already lost weeks.

Agree when payment is due, explicitly. "Net 30" means nothing to many small clients. "Payment due within thirty days of the invoice date" cannot be misread.

Find out who actually pays. Your contact is often not the person who releases money. Larger organisations have an accounts email and a payment run on a fixed day. Ask at the start: who should the invoice go to, and is there a purchase order number required? An invoice sent to the wrong person can sit for a month before anyone notices.

Take a deposit on anything substantial. Thirty to fifty percent upfront. This filters out clients who were never going to pay and protects you on the rest. Clients who refuse any deposit are telling you something.

The invoice itself

Nothing exotic. What matters is that nobody has to ask a question before paying.

• Your name or business name and contact details
• Their business name and the correct billing contact
• A unique invoice number, sequential
• Invoice date and payment due date as an actual date, not a duration
• A clear line-by-line description of what was delivered
• The amount, and tax if applicable, and the total
• Payment details — bank account, or a payment link
• Their purchase order number if they use them

The most common cause of a stalled invoice is a missing PO number. It gets rejected by their system and often nobody tells you.

Send it as a PDF. Not a document that can be edited, not a spreadsheet, not text in an email body.

When to send it

Immediately on completion. The same day. Your work is freshest in their mind and the value is obvious. An invoice arriving three weeks later feels like an old obligation.

For long projects, invoice in stages. Monthly or at milestones. Never carry three months of unbilled work — that is your money funding their business.

Check their payment run. Many businesses pay on fixed days. If they run payments on the 25th and their terms are thirty days, an invoice arriving on the 26th waits an extra month. Sending it a day earlier can mean being paid four weeks sooner.

Tracking what is outstanding

A simple sheet, one row per invoice: invoice number, client, amount, date sent, due date, date paid, status.

Two formulas do the work.

Days overdue:

=IF(AND(F2="",E2<TODAY()),TODAY()-E2,"")

Where F is date paid and E is due date.

Total outstanding:

=SUMIF(F:F,"",C:C)

That second number is what your clients currently owe you. Most freelancers are surprised by it, and it is the single most useful figure for understanding your cash position.

Conditional-format anything over thirty days in red.

Chasing, without damaging the relationship

Non-payment is usually disorganisation, not refusal. Treat it that way and you keep both the money and the client.

Day one overdue — a short, neutral email. "Hi — invoice 0142 was due yesterday, just checking it reached the right person. Copy attached." Assume an administrative slip, because usually it is.

Day seven — reply on the same thread. "Following up on this one. Could you let me know when it is scheduled for payment?" Asking *when* rather than *whether* is a small distinction that works.

Day fourteen — phone. Email is easy to ignore and easy to lose. A short polite call resolves a surprising proportion in one conversation.

Day thirty — firmer, in writing. State the invoice, the amount, how overdue it is, and a specific date by which you need it settled. Mention that further work is on hold until it is cleared, if that is true.

Day forty-five — escalate. A formal demand, a small claims process, or a collection service depending on the amount and your jurisdiction. By this stage the relationship is already damaged by their behaviour, not by your response to it.

Send every chase from the same email thread. It builds a visible record and saves you reconstructing the history later.

Making it easier to pay you

Friction costs you weeks.

Offer more than one payment method. Put the bank details on the invoice itself, not in the email body where they get lost. If you use payment links, make the link obvious.

Consider a small early payment discount — two percent for payment within seven days. On a thousand dollar invoice that is twenty dollars to be paid three weeks sooner. Whether that is worth it depends on how tight your cash is.

The client worth losing

Some clients pay late as policy. They know exactly what they are doing and they do it to everyone.

You will recognise them: every invoice needs chasing, there is always a process reason, the money always arrives eventually but never on time.

Work out what that costs you — the chasing time, the cash flow strain, the mental weight of carrying it. Then decide whether the work is worth it. Frequently it is not, and the space freed up gets filled by someone who pays on time.

That decision is easier when you have the outstanding figure in front of you, which is the real argument for tracking it at all.