Editorial & Methodology Policy

Last updated: 20 April 2026

BuildMetricLab exists to give UK homeowners, self-builders, and

trade professionals accurate, no-nonsense quantity and cost

estimates for common construction tasks.

Principles

1. Show your working. Every calculator shows the exact formula

used. If you don't agree with the method, you can reproduce the

calculation yourself.

2. Cite the source. Where a calculator depends on industry

benchmarks (e.g., bricks per m², density, Part L U-values) the

reference is listed under Sources & Methodology.

3. Estimates, not promises. We include standard wastage

percentages and mark clearly where site conditions invalidate

a number. We do not claim exactness the numbers cannot deliver.

4. No sponsored output. Affiliate partners have zero influence

on calculator formulas or defaults.

5. Versioned math. When we update a formula, the tool's

`last_updated` date changes and the change is recorded in the

site changelog.

How we source prices

Default unit prices reflect typical UK builders' merchant trade

prices in April 2026 unless otherwise noted. Prices are editable in

every calculator so you can plug in your own quote.

Contributor sign-off

All calculators are reviewed before publication for:

• Formula correctness against a reference textbook.
• Unit consistency (metric first, imperial toggle where relevant).
• Disclaimer completeness for the tool's risk class.
• UK English spelling and terminology.

Corrections

Email [email protected] or use the feedback button on

any tool page. We aim to respond within five working days.