Continue your plan
Useful next calculations
Rates & 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 realistic UK planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
| Input | Value |
|---|---|
| Current Property Value (£) | £250,000 |
| Expected Annual Growth Rate (%) | 5% |
| Projection Period | 5 years |
| Outstanding Mortgage (£) | £200,000 |
After entering these figures, review future property value, total gain and gain (%) together rather than in isolation. Then rerun the tool with one input adjusted.
How to read your results
Future Property Value
The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.
Total Gain
The headline outcome of this calculation. It is most useful when read alongside the supporting metrics rather than in isolation.
Gain (%)
The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.
Future Equity
The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.
Equity Growth
The figure produced by this output for the inputs you entered. Change one variable at a time if you want to see what drives it.
Method & assumptionsAuthoritative sources
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.
Frequently asked
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