Invoice, receipt, quote or estimate: what's the difference?

The short version

Estimates

An estimate is an educated guess. It's useful when you can't know the full scope until you start, such as a repair behind a wall or an agency week whose hours aren't confirmed. Label it clearly as an estimate, explain what it's based on ("about 3 days at £180 a day"), and say what could change it. If the final figure is going to be much higher, tell the client before you get there, not on the invoice. Surprises at invoice stage are the commonest cause of late payment.

Quotes

A quote is a firmer offer: a fixed price for a defined piece of work. Once the client accepts it, the price is generally what you've agreed, so the description of the work matters as much as the number. A good quote includes:

• exactly what's included and, just as useful, what isn't;
• the price and whether it includes materials;
• how long the quote is valid for (e.g. 30 days);
• any deposit or stage payments, and your payment terms.

If the client changes the job, put the change and its price in writing (a text or email is fine) before you do the extra work. Then the invoice can refer to "quote Q-014 plus agreed variation of 12/10".

Invoices

An invoice is a request for payment for work you've done or goods you've supplied. GOV.UK lists what it must include: a unique identification number, your name and contact details, the customer's name and address, a clear description of what you're charging for, the supply date, the invoice date, the amounts charged, VAT if applicable and the total owed. Our sole trader invoice requirements page goes through each item.

Unlike a quote, an invoice is part of your business records. It counts towards your income, and you need to keep it. It should have the next number in your sequence (see our numbering guide), and once sent it shouldn't be quietly edited.

Receipts

A receipt confirms that money has been received. Shops give them automatically. Contractors rarely need to, because a bank transfer is its own record, but some customers ask for one, especially homeowners paying cash. A receipt should show the date, the amount paid, how it was paid, and which invoice it settles ("Received £540.00 by cash on 14/10/2026 in full settlement of invoice 00061"). For your own records, a receipt or bank statement entry is the evidence that the invoice was paid.

Worked example: one job, four documents

A decorator is asked to paint a hall, stairs and landing.

1. Estimate: on the phone, "probably 3 days, so around £540 at £180 a day plus paint".
2. Quote Q-014: after a visit, £540.00 labour for 3 days, plus paint at cost, estimated at £85.00. Valid for 30 days.
3. Invoice 00061: after the job, labour £540.00 and paint £92.40 (receipts available), totalling £632.40, due in 7 days.
4. Receipt: the customer pays £632.40 by bank transfer, and the decorator emails a one-line confirmation on request.

The paint figure moved from £85.00 to £92.40, which is fine because the quote said "at cost". The labour didn't, because it was quoted as a fixed price. Had the quote been unclear about materials, that £7.40 is exactly the kind of difference that turns into a dispute.

Common mix-ups

• Sending a quote titled "Invoice". It can look like a bill for work that hasn't happened. Always title documents correctly.
• Treating an estimate as a fixed price, or letting a client treat it as one. Say "estimate" and give the basis.
• Giving quotes and invoices the same numbers. Use a separate series for quotes (Q-001…) so your invoice sequence stays clean.
• Using a receipt instead of an invoice. A business client will usually need a proper invoice for their own records.
• Recording a pro forma as income. A pro forma invoice is a preview or a request for payment in advance, not a real invoice, so raise the proper invoice once the work or payment happens.

Is a quote legally binding?

A quote that the customer accepts generally becomes part of the contract, so you're expected to do the work for that price unless the job changes. That's why a good quote spells out what's included, what isn't, and how long the price stands (for example "valid for 30 days"). If the customer asks for extra work, put a new price in writing before you do it, then show it as a separate line on the invoice. An estimate is an informed guess, so the final bill can differ, but a big unexplained jump will still cause a dispute. Tell the customer early if costs are running over.

Which one do you need? A quick checklist

• Customer asking "roughly how much?" → estimate.
• Customer about to say yes and wants a fixed price → quote.
• Work done (or a stage done) and you want paying → invoice.
• Money received and the customer wants proof → receipt.
• Need payment before you start → a pro forma invoice.

Download a free quote template or invoice template, and check an invoice with the invoice checker.