Gross development value (GDV) is what a scheme will be worth once it is built and sold. For a housing site, that means the total of every unit's expected sale price on completion. Planning practice guidance in England puts it in one line: "Gross development value is an assessment of the value of development."
Almost every other number in a development appraisal hangs off it. Land price, profit, the size of the development loan and the viability case put to the council all start from GDV, so an error here moves through the whole appraisal.
This guide works through a 12-house example using real sold evidence from one Nottinghamshire outcode. How do you get from comparables to a GDV a lender will accept?
What is GDV in property?
GDV is the expected market value of the completed development, on the assumption that it is finished today. For homes for sale, it is the sum of the sale prices. For build to rent or commercial space, it is the capitalised net rental income. Planning practice guidance also says grant and other external funding should be considered.
Three points trip people up:
- It is gross. Sales costs, build costs and profit come off afterwards. GDV is the top line.
- It is a special assumption. A valuer values the scheme as if complete, which it is not on the valuation date. Savills describes this as a supposition that "could be true in the future" but is not the case today.
- It is unit by unit. You do not apply one area average to the whole site. A two-bed terrace and a four-bed detached house sell at different prices per square foot.
Where does the £ per sq ft figure come from?
From sold comparables: recent sales of similar homes nearby, divided by their floor area. Asking prices tell you what vendors hoped for. Completed prices tell you what buyers paid.
To show what real evidence looks like, we pulled sold comparables for NG12 (Radcliffe on Trent, Nottinghamshire) from Propalt in October 2026. We kept sales with an HM Land Registry price registered between April 2024 and August 2026 and a recorded floor area, then converted to £ per sq ft.
| HOUSE TYPE | SALES | MEDIAN £ PER SQ FT | RANGE |
|---|---|---|---|
| Terraced (2 and 3 bed) | 4 | £338 | £267 to £380 |
| Semi-detached (2 to 4 bed) | 6 | £266 | £217 to £308 |
| Detached (3 and 4 bed) | 7 | £328 | £272 to £346 |
Source: Propalt (October 2026), sold comparables in NG12, HMLR prices registered April 2024 to August 2026. Small samples of second-hand homes.
Two lessons sit in that table. First, the samples are small and the ranges wide, so one sale can move a median. Second, smaller homes often achieve a higher rate per square foot. The terraced homes here were mostly 44 to 54 sq m, which is why they out-price larger semis on a per-foot basis. Apply a rate from homes of a similar size to the unit you plan to build.
These are second-hand sales. New-build homes often sell at a different level, so a valuer will look for new-build evidence nearby and adjust for it.
Through the Propalt MCP, you can ask Claude or ChatGPT for sold comparables for a property and get each one's HMLR price, sale date, floor area and price per square metre back, which is how the table above was built.
How do you do a GDV calculation? A 12-house worked example
Take a hypothetical scheme of 12 houses in the same outcode. The rates below are appraisal assumptions informed by the table above. They are not Propalt figures.
| UNIT TYPE | UNITS | SIZE (SQ FT) | £ PER SQ FT | PRICE PER UNIT | TOTAL |
|---|---|---|---|---|---|
| 2-bed terrace | 4 | 650 | £300 | £195,000 | £780,000 |
| 3-bed semi | 5 | 900 | £290 | £261,000 | £1,305,000 |
| 4-bed detached | 3 | 1,400 | £325 | £455,000 | £1,365,000 |
| Total | 12 | 11,300 | £305 blended | £3,450,000 |
The terrace rate sits below the terraced median because these units are larger than the comparables. The semi rate sits near the top of the semi range because the smaller semis in the sample (77 to 89 sq m) sold at £268 to £308 per sq ft. The detached rate sits close to the median.
Then sense-check each unit price against what buyers have paid in cash terms. A £455,000 four-bed is in line with the £430,000 to £550,000 that four-bed detached homes in the sample sold for. If your unit prices sit above every local sale, your GDV needs a reason.
A GDV is only as good as the three or four sales it rests on. Show the lender those sales, not just the total.
How does GDV give you a residual land value?
The residual method works backwards. Start from GDV, deduct every cost of development including profit, and what remains is the most you can pay for the land.
Planning practice guidance states that 15 to 20% of GDV "may be considered a suitable return to developers" for plan-making viability. Lenders and investors set their own targets, but it is a common reference point. The other costs below are illustrative assumptions, not market data. Use a quantity surveyor or BCIS for real build costs.
| LINE | ASSUMPTION | AMOUNT |
|---|---|---|
| GDV | From the table above | £3,450,000 |
| Build cost | £150 per sq ft × 11,300 sq ft | £1,695,000 |
| External works and infrastructure | 10% of build | £169,500 |
| Professional fees | 8% of build | £135,600 |
| Contingency | 5% of build | £84,750 |
| Sales and marketing | 2.5% of GDV | £86,250 |
| Finance | Illustrative lump sum | £120,000 |
| Developer profit | 20% of GDV | £690,000 |
| Residual land value | Before land purchase costs | £468,900 |
A real appraisal also deducts affordable housing, Community Infrastructure Levy, section 106 contributions and land acquisition costs. Each one reduces the residual.
The residual is also the ceiling you take into land negotiations. Our guides to land assembly and grey belt land cover two common routes to a site where that ceiling decides the deal.
How do lenders use GDV?
Development lenders size the facility against GDV. Loan to GDV (LTGDV) is the total facility, covering land and build, divided by the completed value.
As of October 2026, Hampshire Trust Bank states a maximum of "65% Gross Development Value for experienced property developers", and Aldermore states lending "up to a maximum of 65% of the gross development value". Terms vary by lender, borrower experience and scheme, and other lenders publish different limits. Treat 65% as the published ceiling at those two lenders.
On the example scheme, 65% of £3,450,000 is £2,242,500. Lenders also look at loan to cost, which decides how much equity the developer puts in. The lender's valuer will form their own GDV, and if it comes in lower, the facility shrinks with it.
How sensitive is the residual to GDV?
Very. Holding build costs fixed and keeping profit at 20% of GDV, small changes in sales values produce large changes in land value:
| SCENARIO | GDV | RESIDUAL LAND VALUE | CHANGE |
|---|---|---|---|
| GDV +5% | £3,622,500 | £602,588 | +29% |
| Base case | £3,450,000 | £468,900 | |
| GDV -5% | £3,277,500 | £335,212 | -29% |
| GDV -10% | £3,105,000 | £201,525 | -57% |
| Build cost +10% | £3,450,000 | £260,415 | -44% |
A 10% fall in sales values removes more than half the land value in this example. That gearing is why developers test GDV against current sold evidence before they agree a land price, and again before drawing the loan.
What data do you need for a reliable GDV?
- Sold prices. Completed prices from HM Land Registry, matched to the property so you can tie each sale to its floor area and type.
- Floor area. Recorded floor areas for each comparable, so you can convert prices to £ per sq ft.
- Local stock mix. What sells nearby by type and bedroom count, so your unit mix follows demand.
- Live market context. Asking prices, reductions and time to sale agreed, which show whether the sold evidence still holds. In NG12, detached homes listed in September 2026 had a median asking price of £500,000 and took 88 days to reach sale agreed, against 76 days for detached homes nationally, according to Propalt's monthly market data.
- Site constraints. Planning history and constraints, which decide whether the unit mix you priced can be built.
Lenders run the same checks on their side. Our article on how AI property data is changing work for brokers and lenders covers how credit teams pull this evidence, and the UK property data API developer guide shows how to query it in code.
For the same checks on a single purchase, see our property deal analyser walkthrough.
📌 KEY TAKEAWAY
GDV is the sum of the expected sale prices of the finished scheme, and every other line in a development appraisal depends on it. Build it unit by unit from sold comparables of similar size, show the evidence, and test it: in the worked example, a 10% fall in GDV cut the residual land value by 57%. Published development lending at Hampshire Trust Bank and Aldermore tops out at 65% of GDV as of October 2026. The Propalt API and MCP server return sold comparables with HMLR prices and floor areas for a UK postcode, so the £ per sq ft behind your GDV comes from recorded sales.
SOURCES & DATA REFERENCES
- Ministry of Housing, Communities and Local Government (last updated 16 December 2025). 'Viability.' Planning practice guidance: GDV definition (para 012), 15 to 20% of GDV return to developers (para 019), benchmark land value. gov.uk/guidance/viability
- Savills (18 March 2021). 'In plain English: Five development land valuation terms.' GDV as value on completion, residual land value, special assumption. en.savills.pt/blog/article/312053
- Hampshire Trust Bank (accessed October 2026). 'Development finance.' Maximum 65% of GDV for experienced developers. htb.co.uk/business/development-finance-business/development-finance
- Aldermore (accessed October 2026). 'Property development finance.' Lending up to a maximum of 65% of GDV. aldermore.co.uk/propertydevelopment
- Spark Finance (accessed October 2026). 'LTGDV: definition and meaning.' LTGDV covers land and build; difference from loan to cost. sparkfinance.co.uk/glossary/ltgdv
- Propalt (October 2026). Sold comparables, NG12 (Radcliffe on Trent), houses with HMLR prices registered April 2024 to August 2026 and recorded floor area; 17 sales; medians and ranges of £ per sq ft by house type. api.propalt.io
- Propalt (October 2026). Monthly market statistics, NG12 and national, September 2026, via the Propalt MCP (get_monthly_market). Supports the NG12 detached median asking price of £500,000 and the 88 days to sale agreed in NG12 against 76 days nationally.
Contains HM Land Registry data © Crown copyright and database right 2026. This data is licensed under the Open Government Licence v3.0.
