The calculation
Upfront cash
Cash deposit or equity, purchase tax, legal and survey fees, initial works and other purchase costs.
Annual operations
Scheduled rent is adjusted for occupancy, then management, ground rent, service charge and repairs are deducted.
Mortgage and tax
Interest-only or repayment debt service is modelled year by year. Estimated income tax is then deducted using the selected assumptions.
Exit or 30-year hold
On sale, selling costs, estimated CGT and the remaining mortgage are deducted. Without a sale, the model runs for 30 years and includes estimated terminal equity.
Returns
Cash-on-cash shows year-one rental cash flow divided by upfront cash. IRR annualises all modelled investor cash flows.
Investment comparison
The main property dashboard is shown after estimated personal tax. For a more consistent comparison with published market returns, the property line in the historical chart is shown before personal income tax and CGT. It still includes property costs, transaction costs and mortgage payments.
A mortgaged property produces a leveraged equity return. The benchmark investments are unleveraged, so the comparison is useful context—not a claim that the risks are identical.
Scope and sources
The current tax model assumes one individual owner. Purchase tax is selected by UK jurisdiction; CGT uses an editable rate and simplified deductible-cost assumptions. Tax rules and individual circumstances can change the result.
Historical comparison data uses published index, ETF and Bank of England sources linked beneath the chart. Past performance is not a forecast.
Return to the calculatorMethodology last reviewed: September 2026.