Rent coming in is easy to see. The costs going out are spread across the year — a mortgage payment here, an insurance renewal there, a boiler repair, a gas safety check, a few weeks between tenants. This calculator puts them together so you can see your real annual cost and what’s left over.
It runs entirely in your browser. We don’t store or see the numbers you enter.
Annual account
| Item | Low | High |
|---|
Costs before tax. Price ranges come from published 2026 cost guides. Licence fees come from each council’s own page; check the date before relying on one. This is an estimate for planning, not tax or legal advice. See our sources and methodology. Last reviewed: 8 October 2026.
How to use the calculator
- Enter your monthly rent — what your tenant actually pays you.
- Enter your monthly mortgage payment, or tick the box if you own the property outright.
- Enter your property’s value. The calculator uses it to suggest a maintenance budget of 1% of value per year. You can overwrite this.
- Check the insurance, compliance and software figures. They’re pre-filled with typical 2026 figures (explained below) — replace them with your own if you know them.
- Set the void weeks — how many weeks a year you expect the property to be empty.
The results update instantly, showing your effective annual rent, each cost, your total costs and your net position before tax.
Where the default figures come from
We don’t invent numbers. Each pre-filled value is based on a published source, explained in full on the linked page:
| Input | Default | Based on |
|---|---|---|
| Maintenance | 1% of property value | A widely used rule of thumb; compare with survey data in our maintenance costs guide |
| Insurance | £255 a year | Median of £253.42 for buildings and liability cover, Simply Business customers Jun–Aug 2026 — see landlord insurance cost |
| Compliance | £200 a year | Annual gas safety check, EICR and EPC spread over their lifetimes, plus the £65 PRS database fee — roughly £160–£250 for a typical house. See certificate costs |
| Software | None | Free tiers exist for up to 3 properties; paid plans from about £12–£40 a month — see software prices |
| Voids | 3 weeks | The average void period was 23.2 days in 2026, according to Rushbrook research reported by The Intermediary |
A worked example
Take a property worth £220,000, let at £1,200 a month, with a £650 monthly mortgage payment and the default figures above:
| Item | Annual amount |
|---|---|
| Rent received (after 3 void weeks) | £13,569 |
| Mortgage payments | −£7,800 |
| Maintenance (1%) | −£2,200 |
| Insurance | −£255 |
| Compliance | −£200 |
| Software | £0 |
| Net position before tax | £3,114 (about £260 a month) |
Notice how much the smaller items matter together: three weeks of voids alone cost about £831 of the £14,400 headline rent, and maintenance takes more than insurance, compliance and software combined.
What the calculator doesn’t include
To keep it simple and honest, the calculator leaves out things that depend heavily on your personal situation:
- Income tax. Your tax bill depends on your other income and tax band. Mortgage interest relief for individual landlords is restricted to a basic-rate (20%) tax credit, according to GOV.UK, so your taxable profit can be higher than the net figure shown here.
- Letting agent fees. If you use an agent, add their fee to your costs. Published ranges run from around 10% to 20% of monthly rent for full management, per Purplebricks’ guide, plus VAT. Letting agent fees are an allowable expense for tax.
- Mortgage capital vs interest. The calculator uses your full monthly payment, because that’s the cash leaving your account. For tax, only the interest element matters.
- One-off costs. Buying costs, Stamp Duty (including the 5% surcharge on additional homes) and major refurbishments aren’t annual running costs.
- Rent guarantee or extra insurance. Add these to the insurance box if you have them.
For the full picture, including tax, read our guide to the true cost of being a landlord.
How to use your result
- Negative or close to zero? Look first at the biggest lines: mortgage rate, maintenance and voids. A remortgage or a rent review (using the correct Section 13 process) usually has the biggest effect.
- Testing a purchase? Run the numbers with a higher mortgage rate and an extra void month to see how resilient the investment is.
- Planning ahead? Remember that some costs rise over time: insurance renewals, older properties needing more maintenance, and new regulatory fees.
From net position to rental yield
Many landlords judge a property by its yield — the rent as a percentage of the property’s value. The calculator helps you see the difference between the headline figure and the real one.
| Measure | How it’s worked out | Worked example (£220,000 property) |
|---|---|---|
| Gross yield | Headline annual rent ÷ property value | £14,400 ÷ £220,000 = 6.5% |
| Net yield before mortgage | (Rent after voids − running costs) ÷ property value | (£13,569 − £2,655) ÷ £220,000 = 5.0% |
| Cash left after mortgage | Net position from the calculator | £3,114 a year |
Running costs in this example are maintenance (£2,200), insurance (£255) and compliance (£200). A 6.5% headline yield becomes about 5.0% once voids and running costs are included — and that’s before any agent fees or tax.
Three ways to use the calculator
1. Health check an existing let. Enter your real figures from last year: rent actually received, mortgage payments, and what you really spent on repairs and certificates. Compare the result with what you expected.
2. Stress-test a purchase. Enter the numbers for a property you’re considering, then change one thing at a time:
- add 1–2 percentage points to the mortgage rate (by increasing the monthly payment);
- double the void weeks;
- increase maintenance to 1.5% for an older property.
If the net position turns negative under realistic stress, the purchase is riskier than it looks.
3. Compare self-managing with using an agent. Run it once as it is, then add an agent’s fee to the compliance box as a rough stand-in (for example, 12% of rent plus VAT on £1,200 a month is about £2,074 a year). The difference shows what the agent is costing you, so you can judge whether the time saved is worth it.
Why we built it this way
Most online landlord calculators either focus only on yield or ask for dozens of inputs. We kept to the few numbers that make the biggest difference, gave every default a published source, and left out tax because it depends on circumstances no simple calculator can know. For the costs we didn’t include, read the true cost of being a landlord and our guides to insurance and certificates.
Frequently asked questions
Is this calculator free? Yes. There’s no sign-up, and nothing you type is sent to us.
Does it work for HMOs? You can use it, but HMOs usually have higher insurance, licensing, utility and maintenance costs. See our HMO licence cost guide for the extras to add.
Why does it use 1% of property value for maintenance? It’s a common rule of thumb. Older properties often need more; newer ones less. Overwrite it with your own figure if you have one.
Does it include tax? No. Tax depends on your wider circumstances. The result is your position before tax.
Sources for the default values
- MoneySuperMarket — Landlord insurance (Simply Business data, June–August 2026)
- The Intermediary — Average cost of rental void period rises by 58%
- Property Tax Partners — Gas safety certificate cost and EICR cost
- Home Safety UK — EPC cost 2026
- Osborne Clarke — PRS database fee
- Purplebricks — Letting agent fees for landlords
- GOV.UK — Working out your rental income
The calculator gives an estimate for planning only. It is not financial or tax advice. Last checked: 8 October 2026.