If you're paying your own Self Assessment tax bill, you'll usually need to make two payments on account every year. You'll need to make the first payment by 31 January, following the end of the tax year, and make the second payment by 31 July.
You can be fined £100 or more, or be charged interest on late payments, if you miss the deadline to submit a tax return or pay your bill. Make sure you get help as soon as possible if you’re finding it difficult to complete your return. You should contact HMRC as soon as you can if you’ve missed your payment or you're having trouble paying it on time.
You can appeal against a penalty if you have a reasonable excuse – for example, if you had an unexpected stay in hospital and couldn’t complete your tax return in time.
If you’re having trouble making your tax payments due to the coronavirus (COVID-19) pandemic, you can get in touch with the HMRC coronavirus helpline.