Builder's quote vs estimate — the difference that decides who pays for overruns
The short answer: a quote (quotation) is a fixed price for defined work — legally, an offer that becomes binding when you accept. An estimate is an informed guess that can move. Which one you hold decides how "the price went up" arguments end — and a fixed quote for the defined scope is very hard for a builder to escape.
REVIEWED BY: Sean McNamara on 2026-09-03
The legal difference
- Quotation: a definite offer — scope, price, validity. Accept it (signature, email "go ahead") and a contract exists at that price for that scope. The Consumer Rights Act 2015 sits on top: the work must still be done with reasonable care and skill (s.49).
- Estimate: not an offer; an expectation. The final bill can lawfully differ if the change reflects genuine variations, unforeseen conditions, or scope adjustments agreed along the way. It is not licence for open-ended drift: any charge beyond the estimate still needs a real justification and, ideally, your written sign-off.
- "Price on application" / day-rate jobs: agree a maximum ("not to exceed £X without my written agreement") — without a cap, you carry all the risk.
What the paperwork must contain (either way)
1. Itemised scope — rooms, tasks, materials, what's excluded (skips, scaffolding, decorating after plastering…). 2. Price basis — fixed sum, day rate + materials, or stage payments. 3. Duration — start date and reasonable completion. 4. Variation procedure — any change to scope/price must be in writing before the work changes. 5. Payment stages tied to completed, inspected work — with a retention (5–10%) until snagging is finished. 6. Validity — quotes should state how long they hold (materials prices move).
Where disputes actually start
- "It was more work than we thought" — a risk the builder prices in when quoting; discovering rotten joists they saw when quoting is their discovery, not your variation.
- "You changed your mind" — that IS a variation, chargeable if agreed in writing. The fight is nearly always about whether it was agreed, which is why the written-variation rule decides cases.
- Verbal site instructions — a handshake change order. If it happens, text-confirm immediately: "Confirming today's change: [X] for £[Y] as discussed." A dated message converts talk into evidence.
The mid-job money demand
If they demand more to continue the same scope under a fixed quote, that's the builder walked off the job scenario: don't panic-pay; state the contract position in writing; keep the evidence file growing.
Practical tip for hiring
Ask every bidder for a fixed quote against your written scope, not an estimate — the discipline of itemising also separates the organised builder from the cowboy before work starts. Then keep it with your evidence file.
This page is general information, not legal advice. Verified 2026-09-03.
Preparing a claim? EvidenceCanvas (Casewright) helps you organise your evidence and draft pre-action documents for the small claims track. It is not a law firm and does not give legal advice.
Reviewed by Sean McNamara · 2026-09-03 · Independent information directory — not legal advice.