House Extension Cost Calculator
Work out the cost of your house extension instantly — free cost calculator with a guide price in seconds, then a detailed fixed estimate if you want one.
House Extension Calculator
Adjust the options below for an instant estimate.
Estimated Total
This is an instant guide estimate based on the details you enter. Every project is different — we always confirm with a detailed, fixed written estimate after a site visit.
Want this estimate in writing? (optional)
Leave your details and we'll follow up with a detailed quote. Or just use the estimate above — no details needed.