Interim invoice
template

Waiting until the end of a long job to be paid ties up your cash and your risk. An interim invoice bills the work done so far, usually monthly, so money comes in while the job runs. On construction jobs lasting 45 days or more, the law gives you a right to interim payments. This template shows the value of work to date, what has already been invoiced, and the amount due now.

When to use a interim invoice

Use an interim invoice on any job that runs for weeks or months: a refurbishment, a software build, a long consultancy engagement, or a series of deliveries. Agree the interval and the basis, monthly valuation, percentage complete, or time spent, before you start. For fixed milestones, such as "first fix complete", a stage payment invoice is a better fit. When the job finishes, issue a final invoice for the balance.

What a interim invoice must show

An example interim invoice

The template comes filled in with example lines like these, so you can see how each part works before replacing them with your own.

Line by line: Interim valuation 2: work completed 1 to 30 [Month], 1 × £6,400.00 = £6,400.00. The subtotal is £6,400.00, VAT at 20% adds £1,280.00, and the amount due this invoice is £7,680.00. The figures are illustrative; replace them with your own.

How to fill in the template

1. Agree the billing interval and valuation method at the start of the job.
2. At each interval, value the work completed to date.
3. Subtract everything already invoiced to find the amount due.
4. Deduct any retention the contract allows.
5. Add VAT if you are registered and send the invoice with a short note of what was done.
6. Keep a running schedule so each invoice ties to the last.

Give each interim invoice its own number in a single sequence, and never reuse one. A number lets you and your customer refer to the document without confusion, and an unbroken sequence shows your records are complete. The invoice number generator suggests a format that stays tidy for years.

The right to interim payments in construction

Under the Housing Grants, Construction and Regeneration Act 1996, a party to a construction contract is entitled to payment by instalments, stage payments or other periodic payments, unless the work is specified or agreed to last less than 45 days. The parties can agree the amounts and intervals; if they do not, the Scheme for Construction Contracts fills the gap. The Act does not apply to contracts with a residential occupier for work on their own home. Outside construction, interim billing depends entirely on your contract, so write the interval and basis into your terms.

Interim invoice or stage payment invoice?

Interim invoices follow time: monthly valuations of work done. Stage payment invoices follow milestones: an agreed sum when each stage is complete. Time-based billing suits jobs where progress is steady; milestone billing suits jobs with clear stages.

Valuing work in progress

Interim valuations can be based on measured work, such as square metres of plaster laid; on percentage complete against a priced schedule; or on time and materials used. Whatever the method, agree it in advance and apply it consistently. Send a short schedule with each invoice, listing the items and their value to date. A clear valuation is harder to dispute and makes it easier for a customer's surveyor or project manager to approve the payment quickly.

VAT on interim invoices

For VAT, construction services supplied under a contract with periodic payments are treated as supplied each time a payment is received or a VAT invoice issued, whichever is earlier. The same continuous-supply rule applies to many other services billed periodically. Each interim invoice therefore carries VAT on its own amount. If you prefer not to account for VAT until you are paid, you can send an application for payment first, which is not a VAT invoice, and issue the VAT invoice once the payment arrives.

Applications for payment

On larger construction jobs, the subcontractor submits an application for payment, the contractor responds with a payment notice stating the sum they consider due, and the invoice follows. The Construction Act sets timescales for these notices and for any pay less notice if the payer intends to pay less. If the payer fails to serve the right notices in time, the sum applied for may become the notified sum. Read your contract's payment clauses carefully, as the dates matter.

Retentions

Many construction contracts let the payer hold back a percentage of each interim payment, often 3% to 5%, as retention against defects. Half is usually released at practical completion and the rest after the defects period. Show the retention on each interim invoice so the figures are transparent, and track what is held so you can invoice its release on time. Our guide to retention payments in construction covers the detail.

Interim billing outside construction

Consultants, developers and agencies use interim invoices on long projects too, typically monthly for time spent or percentage complete. Put the billing interval in your proposal, set a payment term such as 14 or 30 days, and send each invoice on the same day each month so it becomes routine for the customer. On large projects, a small upfront invoice and monthly interim invoices reduce your exposure if the customer stops paying.

Common interim invoice mistakes

• Billing the cumulative value instead of the increase. Deduct what has already been invoiced each time.
• No agreed interval or valuation method. Agree both before you start, in writing.
• Losing track of retentions. Record what is held so you can invoice its release.

Checklist before you send it

Before a interim invoice goes out, check it against the list of what it must show:

• A unique invoice number and date, and the job reference is on it and correct.
• Your details and the customer's is on it and correct.
• The period or valuation date the invoice covers is on it and correct.
• The value of work completed to date is on it and correct.
• What has been invoiced before is on it and correct.
• The amount due now, with VAT if registered is on it and correct.
• Any retention deducted, if the contract has one is on it and correct.
• A copy is saved with your records.

Sending it

Send the interim invoice as a PDF attached to an email, not as an editable file. In the email, say what it is, its number, the amount and any date that matters, so the reader can act without opening the attachment. Send it to the person or inbox that deals with it, which for a business is often an accounts address rather than the person you worked with, and keep a copy of the email and the PDF together in your records.

Keep a copy

Keep a copy of every interim invoice you issue or receive, digital is fine, with the payments that relate to it. From 6 April 2026, sole traders and landlords with qualifying income over £50,000 must keep digital records and send HMRC quarterly updates under Making Tax Digital, falling to £30,000 from April 2027 and £20,000 from April 2028. The MTD requirement checker shows when it applies to you, and how long to keep invoices covers retention.

Download the interim invoice template

The template comes as a Word document for Word, Google Docs and Pages, an Excel workbook for Excel and Google Sheets, and a print-ready PDF. Replace the words in square brackets with your own details. In the Excel version each line, the subtotal and the total are formulas, so the figures update as you type. Or fill it in online with the free invoice generator, which makes a finished PDF with your details, in your colours.

Related documents in the same family: the deposit invoice template, stage payment invoice template, final invoice template, retainer invoice template and hourly invoice template. All of them follow the same numbering and record-keeping rules, and each page explains what that document must show.

A TapTax account, free to start, creates and sends invoices, tracks which are paid, keeps receipts and bills with your records, and files your quarterly updates to HMRC from the same data.