Portfio / Tools and guides / Capital Gains Tax calculator

Free tool · UK residential property

Capital Gains Tax calculator for selling a buy-to-let.

Estimate the Capital Gains Tax on a rental property you sell. Enter what you paid, what you sold for and your costs. We apply the tax-free allowance and the 18% and 24% rates.

An estimate for planning, not tax advice. It is for individuals and does not cover your own home, companies or trusts.

Rates checked against GOV.UK on 7 November 2026.

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Your sale

Example values

Figures update as you type.

01The property

Purchase price

What you paid for the whole property.Enter an amount over £0.

Sale price

The agreed sale price for the whole property.Enter an amount over £0.

Buying costs

Solicitor’s fees and other costs of buying.Enter an amount of £0 or more.

Selling costs

Estate agent and solicitor fees when you sell.Enter an amount of £0 or more.

Capital improvements

For example an extension. Not repairs or decorating.Enter an amount of £0 or more.

Your ownership share

Joint owners each work out the gain on their own share.Enter a share above 0% and up to 100%.

02Your income

Tax year of the sale

Set by the date you exchange contracts, not the completion date. Enter your exchange date below to fill this in.

How to set your rate

Your other income for the year

Salary, pension, rental profit and other taxable income, before the Personal Allowance. Do not include this gain.Enter your income in pounds, or choose higher or additional rate.

03Allowance and dates

Tax-free allowance already used this tax year

Gains on other assets in the same tax year that used some of your £3,000.Enter between £0 and £3,000.

Exchange of contracts (optional)

Sets the tax year of the sale.This calculator covers sales exchanged between 6 April 2025 and 5 April 2027.

Completion date (optional)

Starts the 60-day clock to report and pay.Completion cannot be before exchange.

Date you bought it (optional)

Shows how long you owned it. Property owned before April 1982 uses different rules.

04About you and the property

Were you UK resident for tax when you sold?

Did you ever live in it as your main home?

If you did, Private Residence Relief may reduce the gain. This calculator does not apply it.

Example values are illustrative only. Replace them with your own figures.

Estimated Capital Gains TaxResult from example values

£0

on a taxable gain of £0

18% band24% band

Gain on the whole property: £0
Your share (50%): £0
Tax-free allowance applied: −£0
Taxable gain: £0
At 18% (£0): £0
At 24% (£0): £0
Estimated tax to pay: £0

Report and pay within 60 days You must report and pay any Capital Gains Tax due on UK residential property within 60 days of completion.

This is an estimate, not tax advice. It assumes no losses, reliefs or other gains, and uses your exchange date for the tax year. It is for individuals. It uses the UK £37,700 basic rate band for Capital Gains Tax, which also applies if you pay Scottish Income Tax. Gift Aid and personal pension contributions extend your basic rate band. If you make them, take the gross amount off the income you enter. Figures are rounded to the nearest pound. Check with HMRC or a qualified tax adviser before you act.

01 The figures used

Rates and allowances, 2025–26 and 2026–27.

The same figures apply in both tax years.

Basic rate taxpayers: 18%On gains that fit in your unused basic rate band
Higher and additional rate: 24%On gains above the basic rate band
Tax-free allowance: £3,000Annual exempt amount, per person
Basic rate band: £37,700Taxable income after the £12,570 Personal Allowance

Source: GOV.UK — Capital Gains Tax rates and allowances; Income Tax rates and allowances for current and past years.

02 How it works

What the calculator does, in plain English.

Costs you can deduct

Your gain is usually the sale price minus what you paid. You can then take off:

estate agents’ and solicitors’ fees
other costs of buying and selling
improvement works, such as an extension

Normal maintenance, such as decorating, does not count.

Which rate you pay

Take off the £3,000 allowance. Add what is left to your taxable income.

The part that fits inside the £37,700 basic rate band is taxed at 18%. The rest is taxed at 24%.

Higher and additional rate taxpayers pay 24% on the whole taxable gain.

The 60-day deadline

If you are UK resident and have tax to pay, report and pay within 60 days of completing the sale. Use a Capital Gains Tax on UK property account.

The tax year of the sale is set by the date you exchange contracts. The 60 days run from completion.

You may pay interest and a penalty if you are late.

If you already file Self Assessment, include the sale in your tax return too.

03 Worked example

HMRC’s own example.

From GOV.UK, for a gain made on or after 6 April 2026.

Taxable income (after Personal Allowance): £20,000
Taxable gains: £52,600
Less tax-free allowance: −£3,000
Gain to pay tax on: £49,600
At 18% on £17,700: £3,186
At 24% on £31,900: £7,656
Capital Gains Tax: £10,842

Source: GOV.UK — Capital Gains Tax rates, Example 2.

04 Limits

What this doesn’t cover.

Your own home, or a home you once lived in

Private Residence Relief and Letting Relief can reduce the gain. This calculator does not apply them. Use HMRC’s property calculator or speak to an adviser.

Losses and other gains

Losses on other assets can reduce your gains. Other gains in the same tax year share one £3,000 allowance. Enter any allowance you have already used.

Companies, trusts and estates

Limited companies pay Corporation Tax on gains, not Capital Gains Tax. Trustees and personal representatives follow different rules and allowances.

Gifts, inheritances and pre-1982 purchases

You may need to use the market value instead of the price paid. That applies to gifts, inherited property and property owned before April 1982.

Scotland and non-UK residents

If you pay Scottish Income Tax, Capital Gains Tax still uses the UK rates and the £37,700 basic rate band. Enter your total taxable income as normal. Non-residents must report every UK property sale, even with no tax to pay.

05 Portfio

Before you sell, know your numbers.

Portfio shows value, equity, rent and cashflow across your properties, and models tax and structure side by side, including what a sale would leave you with.

Free for your first two properties, with every feature

Then £4.99 a month on Pro for up to 20 properties, or £9.99 a month on Portfolio for unlimited properties.

Download on theApp Store Get it onGoogle Play

01Dashboard

“Value, equity, rent, cashflow and a 0–10 health score.”

02Refinance

“Which loans need action, and what it is worth.”

03Tax & structure

“Personal, PPR or limited company, side by side.”

Feature wording from portfio.app. Indicative modelling only.

Sources

Figures last checked against these pages on 7 November 2026. We review them every tax year.

Portfio does not provide tax, legal or financial advice. This calculator gives an estimate for planning only.