Two words, used interchangeably on a thousand building sites, that mean completely different things the moment there is an argument about money. If you get this wrong you either lose the difference out of your own pocket, or you end up in a dispute you were always going to lose.
Here is the difference, in plain terms, and the wording that keeps you on the right side of it.
What is a quote?
A quote is a fixed offer. You are saying: I will do this specific work, for this specific price.
The moment the customer accepts it, you have a contract. The price in that contract is the price. If the job turns out harder than you thought, if you underestimated the labour, if the plasterer takes three days instead of two, that is your problem. You quoted it.
The flip side is that a quote is a strong sales document. The customer knows exactly what they are paying and there is nothing to worry about later. For clearly defined work, that certainty wins jobs.
What is an estimate?
An estimate is your considered best guess at what the job will cost, given what you know today. It is not an offer to do the work at that price. It is information the customer uses to decide whether to go ahead.
Estimates exist because some jobs genuinely cannot be priced up front. You do not know what is under the floor. You do not know whether the boiler is on a shared flue. You do not know how bad the render is until it comes off. Pretending otherwise, with a fixed price, means loading in a fat contingency and losing the job to someone who did not.
The label on the document is not what decides it
This is the part that catches people out.
There is no statute in UK law that defines “quote” and “estimate” as legal terms of art. What decides whether you are bound is ordinary contract law: what did the parties actually agree?
So a document with ESTIMATE across the top, containing one confident number, no caveats, no exclusions, and a covering message saying “that’s the price, I can start Monday”, can be treated as a fixed offer. You called it an estimate. You behaved like it was a quote.
It works the other way too. A document headed QUOTATION that says the tiling allowance is provisional and subject to the customer’s final choice is, on that item, an estimate.
Substance beats heading, every time. That is genuinely good news, because it means you control the outcome with the wording in the body of the document, not with the title.
What happens if the final bill is more than the estimate?
For work done for a consumer, the starting point is the Consumer Rights Act 2015. Section 51 says that where a contract does not fix a price, the consumer must pay a reasonable price and no more.
“Reasonable” is not defined by a number. A court or a trading standards officer would look at things like:
- the going rate for that work in your area
- how much extra work was actually done, and why
- whether the additional work was foreseeable when you gave the estimate
- whether you told the customer as soon as you knew
That last point is the one that decides most real disputes. A customer who was rung on Tuesday and told “the joists are rotten, it’s going to be another £600, do you want me to carry on” almost always pays. A customer who finds out at the end, on the invoice, digs in, and they are often right to.
There is another provision worth knowing. Section 50 of the same Act says that information you give the consumer about the service, which they take into account when deciding to go ahead, becomes a term of the contract. If you said on the phone “it definitely won’t go over three grand”, that sentence can bind you even though your written estimate said something looser.
So is there a 10 or 15 per cent rule?
No. You will see that figure repeated all over the internet and it is not in any statute. It comes from general consumer guidance as a rough marker of when an overrun starts to look unreasonable. It is a useful gut check and it is not a legal ceiling. On a genuinely open-ended job with a documented variation, twice the estimate can be perfectly defensible. On a straightforward job with no surprises, 15 per cent over can look like you low-balled to win it.
How to word an estimate so it stays an estimate
Four things. None of them take more than a line.
1. Say the word, and say what it means.
This is an estimate, not a fixed quotation. It is my best assessment of the likely cost based on the information available at the date shown. The final invoice may differ.
2. Say what the estimate is based on. This is the most useful sentence in the whole document, because it converts “you went over” into “the assumption changed”.
Priced on the assumption that the existing pipework is copper and accessible from the loft, and that the walls are solid brick.
3. Say what is excluded. Not vaguely. Specifically. Making good, decoration, asbestos, scaffolding, parking, waste that is not yours.
4. Say how changes get handled.
Any work outside the scope above will be agreed with you in writing, with a price, before it is carried out.
That last one is worth more than the other three combined. It is not a legal shield so much as an operating habit: it commits you to picking up the phone. See how binding an estimate is for what to do when a variation is disputed after the fact.
Provisional sums: the honest middle ground
You do not have to choose between a fixed price for everything and a vague number for everything.
A provisional sum is a line item you price as an allowance, flagged as such, inside an otherwise firm document:
Floor tiles: provisional sum of £480 based on £32/m² supply. Final cost to be confirmed on your tile selection.
The rest of your document stays a quote. The customer gets certainty on the bits that are certain. You are not exposed on the bit that depends on them wandering round a showroom. Most professional-looking estimates in the trades are built exactly this way, and it is covered in more detail in what to include in an estimate.
Which should you give?
Give a quote when the scope is clear, you can see everything you need to see, and you have done the job enough times to price it confidently. Boiler swap like-for-like. Fitting a supplied kitchen. Rewiring a two-bed flat you have surveyed properly.
Give an estimate when there is something you genuinely cannot know until you open it up. Leaks. Damp. Anything behind plaster. Anything involving a building older than you.
Give a hybrid for most real jobs: firm prices on the known work, provisional sums on the unknowns, exclusions listed underneath.
The 14-day cancellation right nobody mentions
One thing that sits alongside all of this and catches out a lot of sole traders.
If you agree a contract with a consumer in their home, or anywhere away from your own business premises, it is an off-premises contract under the Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013. The customer normally gets 14 days to cancel, and you have to tell them so in writing before the contract is made.
If they want you to start inside those 14 days, they need to ask for that expressly. If you never gave them the cancellation notice at all, your right to be paid for work done in that window can be seriously weakened, and failing to provide the information is an offence.
It takes one paragraph and a cancellation form to comply, so put it in your template once and forget about it.
A word on where this stops
This guide is general information about how quotes and estimates work in practice, not legal advice for your situation. Consumer contract rules are enforced by trading standards and the detail shifts. Check the current position on GOV.UK, and if there is real money in dispute, get an hour with a solicitor rather than guessing. An hour costs less than the argument.
The short version
- A quote is a fixed offer. Accepted, it binds you to the price.
- An estimate is a considered guess. It binds you to a reasonable price, not that number.
- The heading does not decide it. The wording in the body does.
- Say what you assumed, say what you excluded, say how changes get priced.
- Ring them the moment the job changes. Almost every dispute is really about being told late, not about the money.
Once you have the wording right, the job is making sure it is on every single document you send, rather than the one you happened to write carefully. That is a template problem rather than a legal one, and it is why TradeScribe builds your assumptions, exclusions and variation wording into every estimate it produces from your notes, instead of leaving it to whether you remembered.