Useful next calculations
Rates and sources
SDLT/LTT/LBTT bands vary between England, Wales, Scotland and Northern Ireland. Use the appropriate calculator.
Source: HMRC / Welsh Revenue / Revenue Scotland. Check the linked guidance and any live quote before acting.
When to use this calculator
- Before buying, renting, refinancing or reviewing a property investment.
- When you want to compare cash flow, tax, yield or ownership costs.
- When you need a fast estimate before speaking to an agent, lender or adviser.
- When you want to see how a rate or price change moves the result.
A worked example
These are the example figures the calculator opens with.
| Input | Value |
|---|---|
| Current Property Value (£) | £300,000 |
| Expected Annual Growth Rate (%) | 3.5% |
| Projection Period | 5 years |
| Outstanding Mortgage (£) | £0 |
For those figures the calculator returns:
- Future property value: £356,305.89
- Total gain: £56,305.89
- Gain (%): 18.80%
- Future equity: £356,305.89
- Equity growth: £56,305.89
Method & assumptions
This calculator projects future property value using a compound annual growth formula: Future Value = Current Value × (1 + annual rate)^years. Compounding means each year's growth is applied to the already-inflated value rather than the original price, which is why long-run projections can appear striking even at modest annual rates. The default growth rate of 3.5% broadly reflects the long-run nominal UK average based on Land Registry House Price Index data, but you should adjust this to match regional expectations — higher for London and the South East, lower for slower-growing regions. Projections are in nominal (cash) terms and do not account for inflation, transaction costs, or future tax changes.
The equity calculation subtracts your stated outstanding mortgage from both the current and projected future value, showing how much of the property's value you would retain if you sold at that point. This assumes the mortgage balance remains unchanged over the period — in reality, capital repayments reduce the balance over time, so your actual future equity will be higher if you continue making repayments. For planning purposes, this tool is best used alongside a mortgage overpayment calculator to model the combined effect of capital repayment and price appreciation on your net position.
Common mistakes
- Comparing rent and ownership costs without including taxes, fees and maintenance.
- Using purchase price alone without testing financing or vacancy assumptions.
- Relying on yield or growth in isolation instead of reviewing the full property case.
- Using the wrong national transaction-tax calculator for the purchase location.
What to do next
- Run a second scenario with a higher rate or lower rental yield.
- Compare the result with a buy-versus-rent or mortgage calculator before making an offer.
- Use the matching national transaction-tax calculator for the purchase location.
- Note the key figures to share with your solicitor or lender.