How it works

1. 1Choose a calculatorTen of them, split between what a project costs to do and what a home costs to run. Search, or pick from the two lists on the homepage.
2. 2Enter your detailsA handful of fields, each pre-filled with a regional default so you always start from a sensible number rather than a blank box.
3. 3Get your resultAn itemised breakdown, not a single mystery figure — with the quantities you would actually order and a comparison you can act on.

• The result updates as you type. No Calculate button, no page reload, no waiting to see whether a change mattered.
• Every figure is itemised. You get the quantity, the unit price and the line total — so you can price it against your own supplier.
• The method is published. Every calculator states its assumptions and what it deliberately leaves out, on the page.
• Region changes everything. Currency, units, default rates and comparison households all switch together, not just the currency symbol.
• Nothing asks who you are. No account, no email wall, no "enter your postcode for a quote".

Default rates are taken from published sources — regulator price data, national fuel price indices, retail price surveys — and each calculator names the source it used and the date it was checked, directly under the page title.

Nothing on this site invents a number to fill a gap. Where a figure genuinely cannot be known from your inputs — a trade day rate, how much of your solar generation you will use yourself — it is exposed as a control you can change, with the assumption stated in plain words next to it.