You’re a freelancer with six clients, you send invoices whenever you remember, and two of them are now three weeks overdue. A simple invoicing routine fixes that with one weekly slot, a template with the right fields and a short chasing schedule, so late payment stops depending on your memory. The rules below cover the UK and the US, and say which is which.
This is general information about money and records, not personal advice. Tax and invoicing rules depend on your country, your business type and whether you’re VAT-registered, so check the official pages linked here or ask an accountant.
What an invoice must show
GOV.UK’s page “Invoices: what they must include” (UK) lists the details that every invoice should carry. VAT invoices need more, and the page says so, and you must use a VAT invoice if you and your customer are both VAT-registered. GOV.UK’s invoicing guide also notes that an invoice is not the same as a receipt, which is an acknowledgement of payment.
| Field | Why it matters |
|---|---|
| A unique invoice number | Lets both sides refer to it and shows your records are in order |
| Your company name, address and contact details | Tells the client who to pay and who to ask |
| The customer’s company name and address | Identifies who owes the money |
| A clear description of what you’re charging for | Prevents “what is this for?” queries |
| The supply date | Shows when the goods or service were provided |
| The invoice date | Shows when the invoice was issued, so both sides can work out when payment is due |
| The amount or amounts charged | The basis of the bill |
| The VAT amount, if applicable | Required if you’re VAT-registered |
| The total amount owed | The figure the client pays |
Sole traders must also show their own name and any business name they use, plus an address where legal documents can be delivered if they trade under a business name. Make the due date and your bank details impossible to miss by putting them next to the total.
An invoice with a vague description and no due date gives a client a reason to wait.
Know when a payment counts as late
The UK has a statutory framework. GOV.UK’s page “Late commercial payments: charging interest and debt recovery” says that if no payment date is agreed, the law treats the payment as late 30 days after the customer receives the invoice or you deliver the goods or service, whichever is later. If a date is agreed, payment must usually be within 60 days for business transactions. Statutory interest on late business-to-business payments is 8% plus the Bank of England base rate, and you cannot claim it if your contract sets a different rate of interest. You can also claim a fixed sum towards recovery costs.
| Amount of debt (UK) | Fixed sum you can charge |
|---|---|
| Up to £999.99 | £40 |
| £1,000 to £9,999.99 | £70 |
| £10,000 or more | £100 |
Source: GOV.UK, “Claim debt recovery costs on late payments”. You can only charge the fixed sum once for each payment.
In the US, those UK rules don’t apply, and late fees and interest depend on your contract and your state’s law. Write your terms into the agreement and the invoice, such as “Payment due within 14 days. A late fee of [x]% applies after that”, and check that the fee is allowed where you work.
Keep the records the tax authority expects
In the UK, GOV.UK says that sole traders must keep records from the day they start trading, to work out profit or loss for Self Assessment (Become a sole trader). In the US, the IRS page on recordkeeping says you may choose any recordkeeping system suited to your business that clearly shows your income and expenses, and that you must keep records as long as needed to prove the income or deductions on a tax return.
In practice that means one place for every invoice you send and every payment you receive, with the invoice number linking the two.
A simple invoicing routine in 20 minutes a week
Pick a fixed slot, such as Friday at 3pm, and do the same five things each week.
- List what’s been delivered. Check your project notes for work that is finished or reached a milestone since last week. (5 minutes)
- Send the invoices. Raise one for each, using your template and a fresh invoice number, and email it with a plain subject line such as “Invoice 2026-041: article, September”. (7 minutes)
- Record payments. Match incoming payments to invoice numbers in your tracker, and mark them paid. (3 minutes)
- Chase what’s late. Check the tracker for anything past its due date and send the next message in the schedule below. (4 minutes)
- Set aside tax. Move your usual share of anything received into your tax account. (1 minute)
A tracker you can build in ten minutes
| Invoice no. | Client | Date sent | Due | Amount | Status | Last chased |
|---|---|---|---|---|---|---|
| 2026-041 | Client A | 2 Oct | 16 Oct | £850 | Sent | – |
| 2026-042 | Client B | 2 Oct | 16 Oct | £1,400 | Paid 14 Oct | – |
| 2026-043 | Client C | 9 Oct | 23 Oct | £600 | Overdue | 24 Oct |
The figures are illustrations of the layout, not a real ledger. A spreadsheet is enough, and the status column is the part that does the work.
A chasing schedule that stays polite
| When | What you send |
|---|---|
| Three days before the due date | A short reminder with the invoice attached again (optional, useful for new clients) |
| The day after the due date | A friendly note: “Just checking the invoice was received and is scheduled for payment” |
| Seven days late | A firmer message with the amount, the due date and your bank details |
| 14 days late | A call or a message to the person who approves payments, and a reminder of your terms |
| 30 days late | A formal letter that mentions interest and recovery costs under the rules that apply to you, and a pause on new work |
Example: a UK invoice for £1,500 to a business client passes its due date unpaid, and your contract sets no different interest rate. At 14 days late, you can email: “Invoice 2026-044 for £1,500 was due on 16 October. Under UK late payment legislation for business payments, I can add interest at 8% over the Bank of England base rate and a £70 fixed recovery sum. Neither of us wants to take that step. Can you confirm the payment date?” The fixed sum is £70 because £1,500 falls in the £1,000 to £9,999.99 band, and the message gives the client a clear way out.
A message you can copy
- Subject: Invoice [number] for [amount], due [date]
- Opening: “Hi [name], I’m checking on the invoice below.”
- The facts: the invoice number, the date sent, the due date and the amount.
- The ask: “Could you confirm the date it will be paid?”
- The close: your bank details and thanks.
Common mistakes
Invoicing late is the biggest. A bill sent six weeks after the work lands in the client’s calendar six weeks late, and you’ve lost the benefit of any payment terms.
Skipping the due date is the second. “Payment on receipt” means different things to different people, so state a specific date.
The third is chasing by phone only. Keep a written trail of each reminder, so you can show what was sent and when if a dispute arises.
The fourth is waiting until you’re angry. Send the first reminder the day after the due date, when it’s a note and not a confrontation.
A routine checklist
- Invoice template with number, parties, description, dates, amounts, due date and bank details
- Payment terms agreed in writing before work starts
- A tracker showing sent, paid and overdue invoices
- A weekly slot for invoicing, payments and chasing
- The chasing schedule saved as email drafts
- Late-payment terms stated in your contract
- One folder for every invoice and receipt, kept for as long as your tax authority requires
- A fixed share of each payment moved to a tax account
Deposits and milestone invoices
For larger projects, split the invoice so that you’re never owed more than you can afford to lose. A common pattern is a deposit before you start, a payment at a midpoint and the balance on delivery. Put the dates and amounts in your contract, and raise each invoice the day the milestone is met. The same invoice fields apply to each one, and each gets its own number.
The takeaway
Send the invoice the day the work is done, put the due date on it, and chase on a schedule you’ve set in advance. Twenty minutes a week and a tracker with a status column does more for your cash flow than any amount of chasing in a panic.
