Rates & sources
SDLT/LTT/LBTT bands vary between England, Wales, Scotland and Northern Ireland. Use the appropriate calculator.
Source: HMRC / Welsh Revenue / Revenue Scotland — figures refreshed at the start of each tax year.
When to use this calculator
- Before buying, renting, refinancing, or reviewing a property investment.
- When you want to compare cash flow, yield, growth, and ownership costs side by side.
- When you need a fast estimate before speaking to an agent, lender, or adviser.
- When you are assessing whether a rental property still makes financial sense after a mortgage rate change.
- When you want to compare the total cost of renting against owning over a five- or ten-year horizon.
A realistic New Zealand planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Monthly Rent (NZ$)
6
Monthly Mortgage (NZ$)
NZ$600,000
Agent Fee (%)
35
Maintenance (% of rent)
NZ$1,400
After entering these figures, review monthly profit, annual profit and profit margin together rather than in isolation — each metric tells a different part of the story. Then rerun the tool with one input adjusted to see which variable has the biggest effect on all three outputs before you settle on a plan.
How to read your results
Monthly Profit
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Annual Profit
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Profit Margin
Use this metric to compare scenarios side by side and understand how changes in the key inputs drive the final outcome. If the figure surprises you, isolate one variable at a time and rerun the calculation to identify which assumption is responsible.
Method & assumptionsAuthoritative sources
This calculator estimates annual and monthly net profit from a residential buy-to-let property in the UK. It deducts allowable operating expenses including letting agent fees, landlord insurance, maintenance reserves, and void period allowances from gross rental income to arrive at a net operating figure. It then applies the Section 24 mortgage interest restriction to calculate taxable income and estimated tax liability based on your specified income tax rate. The result is an after-tax profit or loss figure. The calculator does not account for capital gains tax on eventual sale, depreciation of fixtures, or complex ownership structures such as limited companies. Figures are estimates only; always seek advice from a qualified accountant familiar with property taxation before making investment decisions.
Common mistakes
- !Comparing rent and ownership costs without including taxes, fees, and maintenance.
- !Using purchase price alone without testing the impact of financing or vacancy assumptions.
- !Relying on yield or growth in isolation instead of reviewing the full property case.
- !Forgetting Stamp Duty Land Tax (or its Scottish and Welsh equivalents), which can add thousands to the true cost of purchase.
- !Using optimistic rental growth figures without also testing a flat or declining rent scenario to check downside resilience.
What to do next
- Run a second scenario with a higher rate or lower rental yield to check downside resilience.
- Compare the result with a buy-versus-rent or stamp duty calculator before making an offer.
- Use the related guides below to understand agent fees, legal costs, and ongoing maintenance budgets.
- If you are assessing a buy-to-let, check the gross yield against the net yield after mortgage interest, voids, and management fees.
- Note down the key figures from this scenario to share with your solicitor or mortgage broker so they are working from the same assumptions.
Frequently asked
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End-of-article next steps
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