⚠️ Hey, you are using an outdated web browser.
TaxScouts might not work with your browser. Upgrade here

Let us sort your Self Assessment online. £119, all in. Learn more


The SA303 form is a document that you can fill in and send to HMRC if you’re self-employed and want to reduce your Payment on Account.

You can also use the online Self Assessment service if you don’t want to deal with printing and sending it by post.

Example of using the SA303 to reduce your Payment on Account:

  • you earned £30,000 in the 2018/19 tax year, all from self-employment
  • this is your first Self Assessment tax return
  • by January 31st, 2020, you need to pay £5,435 in Income Tax and National Insurance
  • you also need to pay an advance payment of 50% towards next year’s tax – that’s £2,717.50. This is called Payment on Account
  • by July 31st, 2020, you need to pay the rest of 50% – another £2,717.50. This is called a Balancing Payment
  • but let’s say that you know you’ll earn less this year – only £20,000. You can ask HMRC to reduce your Payment on Account through an SA303
  • however, you don’t actually need to file an SA303 – HMRC will automatically give you a refund if you overpaid through your Payment on Account.

Hey there! We really hope this article helped you. Tax matters can be a dreadful topic at times. We know. That's why we started TaxScouts.
A stress-free way to getting your taxes done.

Have a minute? See how it works

More guides & useful information

Related terms

Let us sort your Self Assessment online. £119, all in.

That’s right. No matter how complicated it gets or why you need to do a return in the first place, it’ll cost £119 to get it done. That includes VAT, last-minute changes and all the support you may need.

How TaxScouts works

Answer a few simple questions

And we mean a few. After a couple of minutes of answering questions online we’ll have everything we need to start preparing your tax return.

Then get paired with a tax return accountant

That’s right, you’ll be matched with a real certified accountant who is best suited to prepare your return. Plus, they’re on hand for questions whenever you need.

We file your Self Assessment for you

Once you’ve signed off your return, your TaxScouts accountant will submit your return with HMRC for you.

That’s it! We told you it was simple.