Capital Gains Tax

6. Report and pay Capital Gains Tax

Report any Capital Gains Tax you need to pay either:

  • straight away in the Report Capital Gains Tax online service (also known as the Real Time Transaction)
  • annually in a Self Assessment tax return

If you need to do a tax return for any other reason, you must report your gains through Self Assessment, even if you use the online service.

If you’re non-resident and sell UK residential property tell HM Revenue and Customs (HMRC) within 30 days, even if you have no tax to pay.

Before you report

You’ll need:

  • calculations for each capital gain or loss you report
  • information from your records about the costs and what you received (the ‘proceeds’) for each asset
  • any other relevant details, such as any reliefs you’re entitled to

Report your gain and pay straight away

You can use the Report Capital Gains Tax online service if you’re a UK resident. You’ll need a Government Gateway account - you can set one up from the sign-in page.

Using this service will activate your personal tax account if it hasn’t been activated already. You can use this to check your HMRC records and manage your other details.

When you use the service you’ll need to upload PDF or JPG files showing how your capital gains and Capital Gains Tax were calculated.

When to report

You don’t need to wait for the end of the tax year - you can use this service as soon as you’ve calculated your gains and the tax you owe.

You must report by 31 January after the tax year when you had the gains.

The tax year runs from 6 April to 5 April the following year.

After you’ve reported your gains, HMRC will send you a letter or email telling you how to pay.

Report in a Self Assessment tax return

Use Self Assessment to report your gain in the tax year after you disposed of assets.

If you don’t usually send a tax return, register for Self Assessment by 5 October following the tax year you disposed of your chargeable assets.

If you’re already registered but haven’t received a letter reminding you to fill in a return, contact HMRC by 5 October.

You must send your return by 31 January (31 October if you send paper forms).

You can get help with your tax return from an accountant or tax adviser.

After you’ve sent your tax return

HMRC will tell you how much you owe. The Capital Gains Tax rate you pay depends on your Income Tax rate.

You’ll need to pay your tax bill by the deadline.

You’ll have to pay a penalty if you send your tax return late, miss the payment deadline or send an inaccurate return.