Quote vs Estimate Dispute Calculator: Check your legal rights under CRA 2015

The short answer: enter your initial quote/estimate, the amount the builder is now demanding, and any agreed extras. This calculator determines your exact legal liability under Sections 50 and 51 of the Consumer Rights Act 2015, computes the disputed overrun, and generates a formal dispute notice you can send to your builder. Runs entirely in your browser — private and confidential.

REVIEWED BY: Sean McNamara on 2026-09-03

Quote & Overrun Statutory Assessment

1. Type of pricing agreement: Check the heading on your initial paperwork or emails.

2. Original Quote / Estimate (£):

3. Builder's Current Demand (£):

4. Agreed Written Variations (£): Only extra work you confirmed in writing.

5. Defective / Unfinished Deductions (£): Cost to repair defects or finish skipped work.

How the law calculates allowable building costs

1. Fixed Quotes: Section 50 CRA 2015

When a builder gives you a quotation and you agree to proceed, a binding contract is created at that exact figure. Under Section 50 of the Consumer Rights Act 2015, any spoken or written statement made by the trader about the service is treated as a term of the contract. The builder cannot unilaterally raise the price because materials became more expensive or the job took longer than expected.

2. Estimates: Section 51 CRA 2015

An estimate is legally an educated guess. If no fixed price is established, Section 51 states that the consumer must pay a "reasonable price" and no more. UK courts look at:

Prevailing local trade rates for similar trades;
Whether the builder notified the homeowner as soon as an overrun became likely;
Whether the homeowner had the option to approve or halt the work.

3. Defective and Unfinished Deductions

Under Section 56 of the CRA 2015, where a trader has failed to carry out the service with reasonable care and skill (Section 49) or failed to repeat defective performance within a reasonable time (Section 55), the consumer is entitled to an appropriate price reduction — up to the full value of the work needed to rectify the defect.

Related guides & tools

This calculator provides indicative guidance based on English contract and consumer protection law. It does not constitute formal legal advice.

Reviewed by Sean McNamara · 2026-09-03 · Independent information directory — not legal advice.