Buy-to-Let Cashflow Calculator

Stamp duty, deposit, mortgage, fees, and net cashflow together. Free, no sign-up.

Stamp Duty (SDLT)
Deposit required
Mortgage payment (monthly)
Letting agent fee (monthly)
Est. net monthly cashflow

Estimate only, for England/Northern Ireland SDLT rates. Assumes an interest-only mortgage and doesn't account for insurance, maintenance, voids, or other running costs. Not financial advice.

What this calculator does

This combines the full upfront and ongoing cost picture of a buy-to-let purchase in one place: the one-off stamp duty bill, how much deposit you'd need to put down, what an interest-only mortgage payment looks like on the rest, typical letting agent fees, and what's left over as monthly cashflow once rent comes in.

It deliberately doesn't try to model everything, insurance, maintenance reserves, and void periods between tenants all vary too much property to property to estimate meaningfully in a generic calculator, so treat the cashflow figure as a starting point for your own numbers, not a guarantee.

Check real prices and rents by postcode

Every UK postcode district's actual current average price and rent, plus real gross and net yield, is on the interactive yield map and each district's own page under Browse areas.

Common questions

What running costs does this buy-to-let calculator include?

Stamp duty, deposit required, the monthly interest-only mortgage payment, and a typical letting agent fee. It doesn't model insurance, maintenance reserves, or void periods, since these vary too much property to property to estimate meaningfully in a generic calculator.

Does this include mortgage interest tax relief?

No. Since the Section 24 changes, landlords get a flat 20% tax credit on mortgage interest rather than deducting it from rental income before tax. This calculator shows pre-tax cashflow and doesn't model your personal tax position, since that depends on your other income and tax rate.

What's a realistic letting agent fee?

Full management typically runs 10-15% of monthly rent, which is why the calculator defaults to 12%. Let-only or tenant-find-only services are usually cheaper, and self-managing has no ongoing agent fee at all, though it takes more of your own time.

Is this calculator only for buy-to-let, or any additional property?

The stamp duty and deposit figures apply to any additional property purchase, since the SDLT surcharge is based on already owning a property, not on rental intent specifically. The rent and cashflow fields only make sense if you're planning to let it out.

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