A quote is a fixed price for defined work that a builder should honour once accepted, subject only to agreed variations. An estimate is a rough, non-binding indication of likely cost that can change once the job is properly assessed. If your paperwork doesn't say which one you've been given, ask — the label affects how firmly you can hold the builder to the figure.
Two words, two different levels of commitment
In everyday conversation people use 'quote' and 'estimate' interchangeably, and plenty of builders do too — which is part of the problem. Legally and practically the two terms carry different weight. A quote is meant to be a firm figure that the builder commits to for the scope described, changing only if the scope changes. An estimate is a considered guess, offered before all the details are known, and is understood to be capable of moving once the job is properly scoped.
The trouble arises when a homeowner receives something labelled loosely, assumes it's a fixed quote, and is then surprised when the final bill is different. Being clear about which one you have, from the outset, avoids that entire argument.
What a quote should mean
- A specific price for a specifically described scope of work
- Should only change if you change the scope, or if something genuinely unforeseen is uncovered once work starts (for example, unexpected ground conditions)
- Any change in price should go through an agreed variation process, in writing, before the extra work is done
- Usually given once a builder has had a proper look at the job — a site visit, drawings, or both
What an estimate should mean
- A rough figure given with limited information — sometimes over the phone, sometimes from a brief description
- Understood by both sides to be an approximation that could move once the job is inspected properly
- Useful for early budgeting, but not something to bank on for a fixed sum
- Should still say roughly what it covers, even if the figure is rough
Why the difference matters for unforeseen costs
The label matters most when something unexpected turns up mid-job — old drains, unstable ground, asbestos, or rot behind a wall that couldn't be seen beforehand. If you were given a genuine estimate, some movement in price for issues that couldn't reasonably have been foreseen is more understandable, provided it's explained and agreed before extra work proceeds.
If you were given a firm quote, the same discovery should still be treated as a genuinely unforeseen event requiring a written variation, agreed before extra cost is incurred — not simply absorbed into a bigger bill at the end. Either way, the builder should stop, explain, price the change, and get your agreement before carrying on. For more on what to do if this doesn't happen, see our guide on builders charging for extra work.
How to tell which one you've actually been given
If the document doesn't say 'quote' or 'estimate' anywhere, ask directly. A reasonable builder will tell you plainly which they mean and, ideally, put the word on the paperwork itself. If a builder is cagey about committing to a fixed price at all, that's worth noting — it may mean they're not confident enough in their own figures to commit, which is itself useful information before you proceed.
Turning an estimate into a quote
If you've only been given a rough estimate and want price certainty before committing, ask the builder to firm it up into a proper quote once drawings and specification are finalised. This usually costs nothing extra and is a reasonable request before any money changes hands.
Practical checklist
- Check whether the document is explicitly labelled a quote or an estimate
- If unlabelled, ask the builder directly which it is
- Confirm what scope and specification the figure is based on
- For an estimate, ask what information is still needed to firm it into a quote
- For a quote, confirm what would allow the price to change (only scope changes or genuinely unforeseen issues)
- Ask for a written variation process regardless of which you've been given
- Don't sign or pay a deposit against a rough estimate expecting it to be the final price
- Get any firmed-up quote in writing before work starts
Good and bad examples
What good looks like
A builder visits the property, takes measurements, reviews drawings, and a week later sends a written document headed 'Quotation' with a fixed price, scope, specification and payment schedule, stating the price is valid for 30 days and will only change through an agreed written variation.
What to push back on
A figure given over the phone after a two-minute description of the job, treated by the homeowner as a fixed price, with no scope or specification recorded — and no discussion of what might cause the figure to change once work starts.
Worked example
Illustrative example only — for illustration, not typical prices
| Feature | Quote | Estimate |
|---|---|---|
| Basis | Detailed survey/drawings | Brief description, limited detail |
| Price certainty | Fixed, subject to agreed variations | Approximate, may move |
| Typical use | Once scope is finalised | Early budgeting stage |
| Changing the price | Requires written variation | Can be revised as detail firms up |
Commonly missed items
- The document not stating anywhere whether it's a quote or an estimate
- No explanation of what could cause an estimate to move once work starts
- No written variation process for either document type
- Assuming a phone-given figure is a binding quote without confirming it in writing
Warning signs
- A builder refuses to say whether a figure is a quote or an estimate
- A rough estimate is treated by the builder as final once you've paid a deposit against it
- Frequent, unexplained upward revisions to a figure that was presented as a firm quote
- No willingness to put a firmed-up price in writing once the job is properly scoped
Questions to ask
- Is this figure a quote or an estimate?
- What information do you need from me to turn this into a fixed quote?
- What could cause this price to change once work begins?
- Will any change in price be agreed with me in writing before extra work is carried out?
- How long is this price valid for?
When to seek professional advice
- If a builder has significantly increased a price you understood to be fixed, and won't explain why in writing, Citizens Advice (citizensadvice.org.uk) can advise on next steps
- If a contract dispute over pricing terms escalates and doesn't resolve informally, consider the Financial Ombudsman Service if a related credit agreement is involved (financial-ombudsman.org.uk), or seek independent legal advice
- If unforeseen structural issues are found, get written confirmation from the builder and, where appropriate, an independent view before agreeing extra cost
Official sources
Frequently asked questions
- Can a builder legally increase the price after giving me a quote?
- A quote is intended to be a firm price for the agreed scope, and increasing it without your agreement is not reasonable practice. Genuine changes — either to scope you've requested or to genuinely unforeseen circumstances — should be discussed and agreed with you in writing before extra cost is incurred. If you're unsure of your position, Citizens Advice (citizensadvice.org.uk) is a good starting point.
- Is an estimate binding in any way?
- An estimate isn't intended to be a fixed commitment, but that doesn't mean a builder can ignore it entirely or inflate it without reasonable explanation. If a final bill is wildly different from an estimate with no clear reason, that's worth challenging.
- Why would a builder only give an estimate rather than a quote?
- Often because not enough information is available yet — no drawings, no finalised specification, or access issues that need investigating first. That's reasonable at an early stage, provided the builder is clear that it's not a final figure.
- Should I pay a deposit against an estimate?
- It's more sensible to wait until the estimate has been firmed into a proper quote with a defined scope before paying a deposit, since paying against a rough figure gives you less to hold the builder to if the final price is very different.
- What should I do if unexpected costs come up during the job?
- Ask the builder to explain what's been found, why it wasn't foreseeable, and to price the additional work in writing before it proceeds. See our guide on builders charging for extra work for how to handle this if it isn't done properly.
Builder Proof UK publishes general educational information for homeowners. It is not legal, structural, surveying, planning, electrical, gas, insurance or financial advice, and it does not replace advice from a suitably qualified professional for your specific project.