Self Assessment for Income Tax: Checklist for QuickBooks

Self Assessment is how you tell HMRC about income that isn’t taxed automatically. Each year you submit a tax return (SA100) for income earned between 6 April and 5 April. You can file online from 6 April after the year ends.

You must send a return if, in the last tax year (6 April to 5 April), any of the following applied:

• You were self-employed as a sole trader and earned more than £1,000 (before expenses).
• You were a partner in a business partnership.
• You had to pay Capital Gains Tax.
• You had to pay the High Income Child Benefit Charge and don’t pay it via PAYE.

You may also need to send a return if you had untaxed income such as property rent, tips or commission, savings interest, dividends, or foreign income. If you are unsure, use HMRC’s online checker.

These are the critical deadlines for the tax year. Missing them could result in penalties, so make sure you plan ahead.

See HMRC’s guidance for the latest Self Assessment deadlines and penalties for late payments.

If you have not sent a return before, register by 5 October. HMRC will send your 10-digit Unique Taxpayer Reference (UTR). If you register after 5 October, HMRC will set a filing deadline three months from the date of their letter or email. Payment is still due by 11:59pm on 31 January.

How to register

1. Create/sign in with a Government Gateway account.
2. Choose the route that applies to you: sole trader, not self employed, or partnership.
3. Complete the steps and wait for your UTR. You need this to file.

What you need to complete your return

• P60, P45 and P11D forms from employment
• Bank interest and dividend statements
• Rental income records
• Invoices and expense receipts if you are self employed

Keep your records for at least five years after 31 January following the end of the tax year. HMRC may ask to see them.

In QuickBooks, you’ll need to set your business type correctly so your tax information appears accurately.

1. In QuickBooks, select the gear icon to open your Account and settings.
2. Select the Company tab, and then Company type. 
3. Set the tax form as Sole proprietor, then Save.

The Income Tax tab will appear in Taxes so your categories map to HMRC’s Self Assessment sections.

Connecting your bank and credit card accounts allows QuickBooks to automatically import your latest transactions every 24 hours.

• Check if your bank is supported by QuickBooks’ bank feed list.
• If not, you can upload transactions manually.

Review your imported transactions to make sure they’re accurate and categorised properly.

• To save time, you can set up bank rules to automate categorisation of recurring expenses.
• Use QuickBooks’ account and detail types to match transactions correctly.
• If you see a duplicate transaction or a personal expense that you don't want included in your Self Assessment tax return, you can exclude or delete transactions.

It's always good practice to keep track of all your income and expenses throughout the year. Staying organised will make it easier for you to fill in your tax return and claim back any expenses.

Let's say you purchased something in cash or you have a transaction that doesn’t go through your bank, you can add these types of expenses manually into QuickBooks.

It’s time to review your income tax return estimate and find out how much you owe HMRC.

• You may owe less if you’ve made payments in advance to HMRC or you if you qualify for income tax relief.
• If you make payments on account, your January total may also include a balancing payment for last year plus the first on-account instalment for the new year.

1. Follow this link to complete the steps in product
2. Select the tax year you wish to view and select Got it.
3. To see the accounts where your expenses are categorised under and the transactions recorded in those accounts, select the category.

QuickBooks will display a breakdown of your income and expenses, mapped to HMRC’s Self Assessment categories. You can export this information to help fill out your return.

Check out the current income tax rates and bands here.

Once you’ve reviewed your estimate, export the report from QuickBooks. You’ll need to manually enter the information into HMRC’s Self Assessment portal.

1. At the bottom of the tax summary, select Export. 
2. Copy the totals from the exported file
3. Sign in to HMRC's online service.
4. Paste your figures into the correct boxes and submit your return.
5. HMRC will confirm your submission with a reference number

You must pay your tax bill by 11:50pm on 31 January to avoid late payment penalties.

If you qualify and filed by 30 December, HMRC can collect via your PAYE tax code; otherwise pay by bank transfer, Direct Debit, card, cheque, or set up instalments. There’s also a second payment on account due 31 July if applicable.

Can’t pay in full?

Contact HMRC to arrange a Time to Pay instalment plan as soon as possible.