How we price: our cost methodology

Every Costwise figure is a from, typical and up-to range built from real UK job pricing, reviewed and dated, and only changed when the numbers actually move.

Where the numbers come from

We build each price band from current UK supplier and installer pricing, industry cost data and published market figures, then sense-check it against what real jobs of that type actually cost. We show three numbers: a realistic from (a simple job done well), a typical (what most people pay) and an up to (a larger or higher-spec job). They are guide prices, not quotes.

How the calculator works

The calculator ranges your job from the same data: by option for some jobs (for example loft conversion roof type), or per square metre or unit for others (for example a driveway or windows), then applies a regional multiplier. It runs entirely in your browser and sends nothing anywhere.

Reviewing and dating

We stamp each guide with the month its prices were reviewed and update figures when the market shifts. We do not bump the date cosmetically: if the number has not changed, neither does the date. That dated honesty is the whole point of Costwise.

What we will not do

We do not invent prices, reviews, ratings or statistics, and we do not let installer or affiliate partners influence the figures. If a price looks wrong to you, tell us at [email protected] and we will check it.