Example result based on the prefilled values.
Monthly Profit
NZ$386.67
Annual Profit
NZ$4,640.04
Profit Margin
32.22%
Continue your plan
Useful next calculations
When to use this calculator
- Before buying, renting, refinancing, or reviewing a property investment.
- When you want to compare cash flow, yield, growth, and ownership costs side by side.
- When you need a fast estimate before speaking to an agent, lender, or adviser.
- When you are assessing whether a rental property still makes financial sense after a mortgage rate change.
- When you want to compare the total cost of renting against owning over a five- or ten-year horizon.
A realistic New Zealand planning example
Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.
Monthly Rent (NZ$)
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.
Official references
Common mistakes
- !Using an assumption that is not supported by a current local quote, bill, statement or official source.
- !Treating a generic estimate as a lender, provider, payroll or tax authority decision.
- !Mixing monthly and annual inputs without converting them consistently.
- !Forgetting location-specific taxes, fees, eligibility rules or payroll deductions where they apply.
- !Testing only one scenario instead of checking how a cautious assumption changes the result.
What to do next
- Run a second scenario with a cautious assumption so you can see the downside clearly.
- Compare the result with the related calculators below before making a decision.
- Check current local rules, eligibility and provider terms before applying or committing money.
- Keep a record of the assumptions so you can update the estimate when a quote, bill or pay figure changes.
- Use the result to prepare better questions for a lender, provider, adviser or employer rather than treating it as a final answer.
Frequently asked
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