How developers work out what a home will sell for

Every development appraisal rests on one figure above all others — what the finished homes will actually sell for. It sits at the top of the sum, and if it's wrong, everything below it is wrong too. So how does a developer arrive at it?

It starts with comparables

The foundation is comparable evidence — comps. You look at what similar homes have recently sold for nearby, worked back to a price per square foot, then adjust for the differences: size, condition, finish, outlook, parking, the floor it's on. Two sources matter most. New-build comparables are the closest guide, because you're selling new. The second-hand market sets the ceiling on what buyers will pay in the area. Local agents, who sell there every week, are worth their weight for a candid read.

Achieved prices, not asking prices

A discipline worth stressing: you value on what homes achieved, not what they're asking. An asking price tells you what a seller hopes for; a sold price tells you what a buyer actually paid. Build your numbers on the second, always.

Test the market's liquidity

Sold prices tell you what has happened; the live market tells you what's happening now — and that matters just as much. What's currently for sale, and how it's moving, is a read on liquidity: how readily homes actually sell in an area. On a portal like Rightmove you can learn a great deal in ten minutes. How long have properties been listed? Are asking prices being reduced? Flick on the “sold subject to contract” toggle — if plenty of homes are showing as sold or under offer, there is real depth of demand. Between the stale listings and the recent sales, you get a feel for both the ceiling and the floor of the local market.

AI tools can now do a lot of this legwork for you, though it's still worth a manual check in places — square footages in particular can be off, and getting those right is the difference between a reliable comp and a misleading one. Purpose-built tools help here: Landstack, for instance, maps detailed comparables pulled straight from Land Registry, with the exact sold price and floor area and often a link back to the original Rightmove advert, and it has an AI function that will draft you an initial comps list to work from.

The market and the competition

Then you widen the lens: the pull of the location — transport, schools, shops — the local target buyer, and, importantly, the competition, including schemes coming down the line. If three other developments are about to launch near yours, that shapes both your pricing and your pace.

What you build changes how it sells

Product matters to sales, too. Apartments generally sell off-plan more readily than houses, which affects cash flow — you can bank exchanges earlier in the programme. Getting the mix right for the local buyer, and presenting it well (a good show home earns its keep), is part of maximising the value a scheme achieves.

If you own land, this is the number that ultimately sets what your land is worth — because, as we've written before, land value is worked backwards from finished sales value. A developer who is optimistic on sales can bid more; one who is realistic protects themselves. Understanding how the figure is built helps you judge whether an offer is grounded or hopeful. Assessing values properly is one of the first things we do on any site — and if you'd like a straight read on what could be built on your land and what it might achieve, we're always happy to talk it through.