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Value the Land. Before You Bid.
The UK developer's residual land value calculator — work backwards from Gross Development Value to find the maximum you should pay for any site.
Try Land Appraiser — FreeResidual Method
Propty uses the residual method — the same approach used by surveyors and developers across the UK. Start with Gross Development Value, subtract every cost, apply your profit margin, and the remainder is what the land is worth to you.
Sensitivity Analysis
Development is full of unknowns. Propty lets you adjust GDV, build costs, and profit margin to see how sensitive your land bid is to changing assumptions. Know your risk before you commit.
Work backwards using the residual method. Start with Gross Development Value — what the finished units will sell for, based on sold comparables not asking prices. Subtract build costs (typically £130–£180 per square foot in 2026), professional fees and finance (roughly 10–15% of build cost), CIL and any Section 106 obligations, and your target profit margin (most developers use 15–20% of GDV; lenders often require 20%). What remains is the residual land value, and that is your maximum bid.
A formal appraisal from a chartered surveyor typically costs £500–£1,500 and takes one to two weeks, depending on site complexity. That is worth paying before you exchange. It is not worth paying on every site you are considering — run the residual calculation yourself first to decide which sites justify the spend.
Residual land value is the maximum price a developer can pay for a site and still make their target profit. It's calculated by taking the Gross Development Value (what the finished units will sell for) and subtracting all development costs — build, fees, finance, profit margin. The residual amount is the land value.
GDV is the total sales revenue from a completed development. It's calculated by multiplying the number of units by their expected sale price, based on comparable evidence from recent local sales. For example, 4 houses at £200,000 each gives a GDV of £800,000.
UK build costs in 2025 typically range from £120-£180 per square foot depending on location, specification, and project size. Standard new-build houses are around £130-£150/sqft. High-spec or London projects can exceed £200/sqft. BCIS data provides regional benchmarks.
Most UK developers target 15-20% profit on GDV for speculative residential schemes. Lenders typically require a minimum of 20% for development finance. Smaller refurbishment projects may work at lower margins. Our tool lets you test different margins to see their impact on land price.
CIL (Community Infrastructure Levy) and S106 (Section 106 agreements) are charges levied by local authorities on new developments to fund infrastructure. CIL is a fixed charge per square metre set by each council. S106 is negotiated on a site-by-site basis and can include affordable housing contributions. Both reduce the amount you can bid for land.