Calculators and checklists

Every tool here runs in your browser. Nothing you type is sent anywhere, stored, or logged — reload the page and it is gone.

They are estimators, not quotes. Each one shows the arithmetic it used so you can check it against your own paperwork rather than trusting a number.

• Repair or Replace Calculator

  Decide whether to repair ageing equipment or replace it, using remaining life and the energy difference rather than a rule of thumb.

• Contractor Bid Comparison Calculator

  Normalise three quotes that include different things, so the cheapest number is not mistaken for the cheapest job.