Comparing a quote with the benchmark
The calculator starts with a benchmark of £2,800–£3,100/m² excluding VAT. Before you compare it with a quote or replace it with your own rates, check that both describe the same work.
What the benchmark is
It is the range common to four published London guides that give non-luxury construction rates excluding VAT. Those guides use different labels, from basic to mid-range, and describe different finishes, so the benchmark covers only the core they share: foundations, structure, roof, standard external glazing, first-fix services and plastering. It is not an average, and it is not a BCS guaranteed quote.
Check the scope
Ask what a quote includes. It may include more than the benchmark, such as floor finishes, decoration, a kitchen or design fees, or less, such as glazing. A higher rate that covers more is not necessarily more expensive overall. One source we checked quoted a shell-only rate that looks cheap but leaves out glazing and internal trades.
Check the VAT basis
The benchmark excludes VAT. Ask whether your quote includes it, and compare on the same basis. The calculator's VAT line is an illustration at 20%, not a statement of what you'd pay.
Using your own rates
You can replace the low and high rates and the date. The result then shows that the rates are yours. Take both from the same source, for the same scope and VAT basis. The listed exclusions still apply, so add those items separately.
Questions worth asking
What is excluded? Is VAT included? Which floor area is the rate based on? When was it given, and for how long does it apply?