Buy-to-let tax calculator

Work out the tax on your buy-to-let property for 2026/27. You're taxed on rental profit — rent minus allowable expenses — but mortgage interest is treated specially.

Since the Section 24 rules, mortgage interest isn't deducted from profit; instead you get a basic-rate tax reduction worth 20% of it. This calculator applies that for you.

Frequently asked questions

Can I deduct my buy-to-let mortgage interest?

Not from profit. Under Section 24 you receive a 20% basic-rate tax reduction on finance costs instead, which is less generous for higher-rate landlords.

Do I pay National Insurance on buy-to-let income?

Generally no — rental profit isn't subject to Class 4 National Insurance the way self-employment is.

Does MTD apply to buy-to-let landlords?

Yes. From April 2026 landlords over the income threshold must keep digital records and file quarterly under Making Tax Digital.

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