True Buy-to-Let ROI Calculator
Calculate real return on investment for rental properties after costs, finance, tax, and vacancy periods.
True rental return details
This calculator auto-updates when values change.
Deduct voids, running costs, finance costs, tax, and fees before trusting the ROI.
True cash ROI
5.9%
After vacancy, costs, finance, and estimated tax, annual cash profit is about £3,862.
Gross annual rent
£16,200
Vacancy loss
£972
After-tax profit
£3,862
Cash invested
£65,000
About This True Buy-to-Let ROI Calculator
True Buy-to-Let ROI Calculator is designed for property decisions where the headline price or monthly payment is not enough. It pulls the main assumptions into one place so you can compare the trade-off before committing money, time, or borrowing capacity.
Basic rental yield can make a property look attractive while ignoring voids, repairs, management fees, licensing, insurance, mortgage interest, tax, and the amount of cash actually invested.
The result is a planning estimate based on the values entered. Property decisions also depend on local markets, lending criteria, tax treatment, regulations, condition, location, and personal priorities.
Example in Practice
A property renting for GBP 1,350 per month may look strong before costs. After vacancy, running costs, finance, and tax, the cash return on the deposit can be much lower.
The point is not to predict the future perfectly. It is to show which assumption carries the most weight and whether the decision still makes sense when the inputs are less optimistic.
How to Use the Answer
Use the result before comparing properties or offers. A lower gross yield with stronger net cash flow can be better than a headline yield that disappears into costs.
Run at least two versions: one realistic case and one cautious case. If the property only works with perfect rent, no repairs, low rates, and continuous growth, the margin may be too thin.
Costs People Often Miss
Property costs often appear outside the main payment. Legal fees, surveys, stamp duty or transfer taxes, insurance, agent fees, vacancy, maintenance, furnishing, service charges, permits, refinancing costs, and selling costs can all change the result.
Timing matters as well. A cost paid upfront is not the same as a cost spread across years, especially when cash could have been saved, invested, or kept as an emergency buffer.
Before You Commit
Tax rules, mortgage interest treatment, capital growth, regulations, and maintenance surprises can materially change real returns. Treat this as a screening tool, not a full investment appraisal.
For large decisions, use the calculator as an early filter and then check the numbers with mortgage documents, real quotes, local comparable data, and professional advice where needed.
How to Use This Calculator
- 1
Enter the property figures
Use the price, rent, mortgage, cost, income, or project values that match the decision you are testing.
- 2
Include less obvious costs
Add maintenance, fees, tax assumptions, vacancy, overruns, or selling costs where the calculator asks for them.
- 3
Review the headline result
Use the main result to compare options, then read the supporting rows to see what drives the answer.
- 4
Test a cautious scenario
Lower income, raise costs, or reduce growth assumptions to see whether the decision still works.
Frequently Asked Questions
What does the True Buy-to-Let ROI Calculator do?v
Calculate real return on investment for rental properties after costs, finance, tax, and vacancy periods.
Is this a full property valuation or investment model?v
No. It is a simplified planning calculator designed to make the main trade-off easier to see.
Can I use this before speaking to a broker or adviser?v
Yes. It can help you prepare better questions, but it does not replace mortgage, tax, legal, surveying, or investment advice.
Why should I run a cautious scenario?v
Property decisions are sensitive to interest rates, repairs, vacancy, prices, and timing. A cautious scenario shows whether the plan has enough margin.