What it covers
Free interactive cost calculator (bungalow + house) backed by paid Build It Estimating Service.
What it costs
Calculator output gated behind form; no headline £/m² floor on the landing page.
What changed recently
Content actively maintained through April-May 2026; Estimating Service positioned as upsell from the free calculator.
Where it fits in a UK knockdown rebuild
Use Build It (Self Build & Design) as one input among several when sizing a KDR. The calculator on this site cross-checks against BCIS, FMB, and HMRC simultaneously so no single reference drives the headline. For the live worked example, see the calculator; for every figure's primary source, see the sources ledger.
Primary source
Verified 2026-06-21 against the source URL above.