New-Build Development Appraisal Calculator
Full development appraisal for new-build projects including GDV, build costs, finance, and profit analysis.
Live Results
Real-time
AI Analysis
Included
Enter Your Details
Expected sale price per square foot
All-in build cost per sqft
Architects, engineers, etc.
Agent fees, legal, marketing
Your Results
Gross Development Value
£1,360,000
Developer Profit
-£18,106
Quick Insights
Save this calculation
Create a free account to save and compare.
What is Dev Appraisal?
The Development Appraisal Calculator is the essential tool for property developers assessing the viability of new-build projects. Whether you're building a single house, a small development of flats, or a larger residential scheme, this calculator helps you understand whether your project will generate acceptable returns after accounting for all costs including land, construction, professional fees, finance, and sales expenses. A robust development appraisal is the foundation of every successful property development. It's what developers present to lenders, investors, and joint venture partners to demonstrate project viability. Getting this right at the outset helps you avoid costly mistakes and ensure your development delivers the returns you need.
How do I calculate dev appraisal?
This calculator uses the residual valuation method, the industry-standard approach for assessing development viability: **Gross Development Value (GDV)** GDV = Number of Units × Average Unit Size (sqft) × Sale Price per sqft This is the total expected sales revenue from the completed development. **Build Costs** Total Build Cost = Total sqft × Build Cost per sqft We then add professional fees (architects, engineers, project managers) and a contingency allowance. **Development Finance** Finance is calculated using compound interest with: - Land fully drawn from day one for the entire project duration - Build costs drawn at 50% average (phased drawdown) - Interest compounds monthly at the specified annual rate **Profit Analysis** - Profit = GDV - Total Costs - Profit on Cost = (Profit ÷ Total Costs) × 100 - Profit on GDV = (Profit ÷ GDV) × 100 Most lenders require 20% profit on cost as a minimum for development finance.
Key assumptions in this calculation
When to use this calculator
Frequently Asked Questions
What profit margin should I target?
Most development lenders require a minimum 20% profit on cost. However, the appropriate margin depends on project risk. Simple, low-risk projects might work at 15-18%, while complex schemes or those in volatile markets should target 25%+. Remember that margin is your buffer against cost overruns and market changes.
What build cost per sqft should I use?
UK build costs vary significantly by location, specification, and project type. As of 2024, typical ranges are: basic spec £120-150/sqft, medium spec £150-200/sqft, high spec £200-280/sqft, premium London £280-400+/sqft. Always get quantity surveyor estimates for accurate appraisals.
How does development finance work?
Development finance typically covers 60-70% of land cost and 100% of build costs (up to 65-70% of GDV total). Interest rates are usually 8-12% annually, charged monthly in arrears. Most facilities are interest-rolled (added to the loan) rather than serviced. You'll also pay arrangement fees (1-2%) and exit fees (0.5-1%).
What is "profit on cost" vs "profit on GDV"?
Profit on cost = Profit ÷ Total Costs - this measures return on money spent. Profit on GDV = Profit ÷ Sales Revenue - this shows profit as a percentage of end values. Lenders typically focus on profit on cost (requiring 20%+), while investors might look at profit on GDV (typically 15-17% on larger schemes).
Should I include contingency?
Always. Contingency is not a luxury - it's essential risk management. Standard contingency is 5-10% of build costs, but complex sites (contamination, listed buildings, difficult ground conditions) may warrant 10-15%. Lenders will insist on contingency and may increase your required margin if it's too low.
Important Disclaimer
Development appraisals are estimates based on assumptions that will change during the project. Always commission professional quantity surveyor cost estimates, up-to-date valuations, and take independent financial advice before committing to a development. Market conditions can change significantly between appraisal and completion.
Ready to grow your property portfolio?
Get expert property investment tips delivered to your inbox.
Trusted by property investors across the UK