AI-Powered Value-add Calculator
Calculate Your Property Value Increase
Discover how much value your extension could add to your home. Our AI analyzes your property details using UK market data and ONS statistics to provide accurate estimates.
Property Details
Tell us about your property
Extension Details
Size and features
Design & Services
Timeline and services
Your Details
Contact information
Results
Your value increase
What property are you extending?
Detached
Semi detached
Terrace
Other
What do you want to extend?
Ground floor
Loft
First floor
Other
How many bedrooms are there?
How it works
What the estimate takes into account
Five short steps cover your property, the extension, design and services, your details and the result. The estimate weighs up the type of property and how many bedrooms it has today, the kind of extension you are planning, its size — small (15 m²), medium (20 m²) or large (30 m²) — the rooms it adds, and whether the fixtures and fittings will be standard or luxury.
The result is a range: the value the work could add to your home. It is based on regional averages from the ONS and does not include the cost of construction — so for the full picture, set it beside the figure from our build cost calculator.
What you can estimate
Extensions, lofts and more
Choose a ground-floor, loft or first-floor extension and the exact type, or pick “Other” for a garage conversion, a garden annex or a two-storey addition.
Ground floor
Rear, side infill, side, wraparound, or side and rear.
Loft
Dormer, mansard, Velux or hip to gable.
First floor
Rear, side or wraparound.
Other
Garage conversion, garden annex, two-storey rear or two-storey side.
What to do next
Weigh the value against the cost
01
Price the build
Run the same project through the build cost calculator to see what it is likely to cost.
02
Check the planning route
Find out whether the extension could go ahead under permitted development rights.
03
Talk it through
To understand the true costs and benefits of an extension, nothing beats talking to our team.
No. It is an estimate of the value an extension could add, based on regional averages from the ONS. It is a starting point for weighing up a project, not a formal valuation.
No — the estimate does not include construction costs. Use the build cost calculator for an indicative cost, then compare the two.
The estimate allows for the quality of what goes in. Choose luxury rather than standard fixtures and fittings and the range rises.
Book a free consultation. We look at your property and your plans, and give you a fixed-price quote for the work, so you can set a real cost against the value it adds.
Plan & Pricing
More ways to plan your project
Every tool is free and needs no account. Use them in any order — each one answers a different question.
