Property Development Finance Calculator
Calculate development loan amounts, interest costs, project profitability and return on GDV — updated for 2026.
Last updated: March 2026
Property Development Finance Calculator 2026
Enter your project details to calculate maximum loan, interest costs, total project cost and projected profit
Typical Development Finance Terms — UK 2026
| Parameter | Typical Range | Notes |
|---|---|---|
| Interest rate (senior) | 7–12% pa | Depends on LTC, scheme size, location |
| Loan-to-cost (LTC) | 65–80% | Some lenders up to 90% with mezzanine |
| Loan-to-GDV (LTGDV) | 60–70% | Maximum loan as % of completed value |
| Arrangement fee | 1–2% of loan | Paid on drawdown |
| Exit fee | 0–1% of loan | Some lenders waive if scheme complete |
| Loan term | 6–24 months | Extendable for larger schemes |
| Minimum loan size | £150,000+ | Some lenders from £50,000 |
| Mezzanine rate | 15–30% pa | Second charge, higher risk |
Expert Guide to Property Development Finance UK 2026
Property development finance is short-term specialist lending used to fund the construction or conversion of residential, commercial or mixed-use developments. Unlike standard mortgages, development finance is drawn down in stages as work progresses, and interest rolls up during the build. Understanding how lenders structure and price development loans is essential for any developer seeking to maximise returns and protect their equity.
Loan-to-Cost vs Loan-to-Value: Key Distinction
Development lenders use two principal metrics to determine the maximum loan:
Loan-to-Cost (LTC)
The loan as a percentage of total project cost (land + build + fees). Typical maximum: 70–80%. Example: £1m total cost × 75% LTC = £750,000 loan, £250,000 equity required.
Loan-to-GDV (LTGDV)
The loan as a percentage of Gross Development Value (end value). Typical maximum: 60–70%. Example: £2m GDV × 65% LTGDV = £1.3m maximum loan. The lower of LTC and LTGDV limits the loan.
The lower of the two calculations always governs. Lenders use LTGDV as an additional safety net — even if LTC is satisfied, the loan cannot exceed a set percentage of the exit value. This is particularly important in rising build cost environments where a project's cost can approach its GDV.
The Drawdown Process
Development loans are not advanced as a single lump sum. Funds are drawn down in stages tied to construction progress. A typical drawdown schedule:
| Stage | Typical % of Build Loan | Trigger |
|---|---|---|
| Initial advance (land) | Land cost (separate) | On completion of land purchase |
| Drawdown 1 — Foundations | 15–20% | Foundations complete, inspected |
| Drawdown 2 — Plate height | 20–25% | Structural frame/walls to wall plate |
| Drawdown 3 — Watertight | 20–25% | Roof on, windows in |
| Drawdown 4 — First fix | 15–20% | First fix M&E complete |
| Drawdown 5 — Practical completion | Remaining balance | Practical completion certificate |
The monitoring surveyor inspects the site before each drawdown and certifies the works completed. This protects the lender from advances against uncompleted work. Developers should factor in drawdown timing when managing cash flow — there is typically a 5–10 business day lag between requesting funds and receiving them.
Senior vs Mezzanine Finance
Most development projects are financed using a combination of senior debt and equity. Where the developer's equity is insufficient to bridge the gap to 100% of cost, mezzanine finance provides an additional layer of debt:
- Senior debt: First charge over the site. Up to 70–80% LTC. Rates typically 7–12% pa. Most protected position.
- Mezzanine finance: Second charge. Fills gap between senior debt and developer equity. Typically lends to 85–90% LTC total. Rates 15–30% pa. Higher risk, higher return.
- Developer equity: The remaining 10–15%. The developer's "skin in the game" — lenders require this to align interests.
- Whole of loan (WOL) products: Some specialist lenders provide a single facility combining senior and mezzanine (up to 90% LTC) for simplicity, though at a blended rate.
Assessing Scheme Viability: Profit Metrics
Two profit metrics are standard in development appraisals:
Profit on GDV
Profit on GDV = Net Profit ÷ GDV × 100
Industry minimum: 15–20%. Below 15% is generally considered marginal — insufficient return for the risk. Target: 20–25%+.
Profit on Cost
Profit on Cost = Net Profit ÷ Total Cost × 100
Industry minimum: 20–25%. A 25% profit on cost is equivalent to roughly a 20% profit on GDV for a well-structured scheme. Funders often use 20% minimum profit on cost as a viability threshold.
Net profit = GDV − total project cost − finance costs − sales agent fees − other disposal costs. Always model a sensitivity analysis: what happens to profit if GDV falls 10%, build costs rise 10%, or the loan term extends by 6 months?
Planning Gain and Its Effect on Returns
Planning gain — the uplift in land value that results from obtaining planning permission — is a major source of developer return, particularly for experienced developers who purchase land without planning ("pre-planning") and then navigate the planning process. A site worth £200,000 as agricultural land may be worth £1.5 million with permission for 10 residential units — the £1.3 million uplift is the planning gain. This "hope value" is reflected in land prices paid at auction and through off-market transactions. Planning gain significantly reduces the land cost element relative to GDV, improving profit margins.
Exit Finance — Bridging the Gap to Full Sales
When a development completes but units have not yet sold, the development loan must be repaid. Exit finance (development exit bridging) replaces the development loan on completion, giving the developer time to sell at full market value rather than accepting discounted bulk purchase offers. Key advantages:
- Lower interest rate than development finance (construction risk removed)
- Frees the developer from the pressure of a rushed sale
- Can be drawn on a per-unit basis, releasing as each unit sells
- Typical rates: 0.4–0.7% per month on balances outstanding
- Typical LTV: 65–70% of completed GDV (or per-unit value)
Exit finance is most valuable in softer markets or for larger schemes (10+ units) where achieving simultaneous sales is unlikely. For smaller schemes in buoyant markets, it may not be necessary.
Typical Developer Margins by Scheme Type (UK 2026)
| Scheme Type | Typical Profit on GDV | Profit on Cost | Key Risk |
|---|---|---|---|
| Residential new build (small: 1–5 units) | 18–28% | 22–38% | Planning, build cost overruns |
| Residential new build (medium: 6–30 units) | 15–22% | 18–28% | Sales velocity, planning conditions |
| Residential conversion / permitted development | 20–35% | 25–45% | Structural surprises, PD withdrawal |
| Commercial-to-residential (PD rights) | 25–40% | 33–67% | Amenity standards, market demand |
| HMO conversion | 15–25% | 18–33% | Article 4 direction, licensing |
| Luxury/high-end residential | 20–30% | 25–43% | Market depth, build quality |
Sources & Methodology
Interest is calculated on the full loan amount drawn equally over the loan term (simplified drawdown model). Actual interest will vary with staged drawdowns — a real appraisal using a month-by-month cashflow will typically show 40–60% of the headline interest figure due to staged drawdowns.
- HMRC / DLUHC — Infrastructure Levy Guidance
- FCA — Bridging and Development Finance Information
- ASTL — Association of Short Term Lenders
Disclaimer: This calculator provides indicative figures for initial appraisal purposes only. Actual finance costs, loan amounts and profit margins depend on lender terms, market conditions and project-specific factors. Always instruct a qualified quantity surveyor and development finance broker before committing to a scheme.