Quarterly tax calculator
If you manage your HMRC reserve in quarterly chunks rather than monthly, this view puts the quarterly figure front and centre alongside the underlying annual estimate.
Updated for 2026/27. Uses UK tax bands and HMRC/GOV.UK guidance. Estimates only — not tax advice.
Calculator checked against GOV.UK and HMRC rules on (how we check).
Calculate sole trader tax Read the guidesYour Self Assessment payment timeline
Based on your estimated bill of £8,431.80 for 2026/27, here is when HMRC expects payment — and why your first January bill can feel much bigger than the tax itself. Estimate only — your exact HMRC figures may differ.
ends 5 Apr 31 Jan 31 Jul Next
31 Jan
Quarterly reserve for Self Assessment
Managing Self Assessment reserves in monthly chunks works well if you are paid monthly. For those with irregular income, project-based earnings or quarterly invoicing cycles, reviewing the reserve quarterly can be more natural.
This calculator puts the quarterly reserve figure front and centre: the annual combined income tax and NI bill divided by four. It is a savings estimate, not an HMRC payment date: use it to set a quarterly review trigger — checking the reserve against what has actually been set aside. In your first year, save more than this: with no payments on account yet, the first 31 January bill is the whole year-one bill plus the first payment on account for year two, up to 150% of a year's tax.
- January deadline: your January bill includes the balancing amount plus the first payment on account.
- Quarterly review: check the reserve in March, June, September and December.
- If income is irregular, recalculate each quarter with updated profit estimates rather than relying on one annual figure.
Rates checked against Budget 2026 Annex A on 30 October 2026. Written and reviewed by James Whitfield against current GOV.UK and HMRC guidance. Estimates for planning only — not tax, accounting or financial advice.
Quarters, Making Tax Digital and when tax is actually paid
Since 6 April 2026, sole traders and landlords whose qualifying income on their 2024/25 return was over £50,000 must use Making Tax Digital for Income Tax. Qualifying income is your total self-employment and property income before expenses, so it is a turnover test, not a profit test. A salary, your share of a partnership's profit, dividends and pensions do not count. The threshold falls to £30,000 from April 2027 (based on 2025/26 income) and £20,000 from April 2028.
If you are in, you keep digital records and send a quarterly update from compatible software for each quarter of the tax year. For 2026/27 the quarters and deadlines are: 6 April to 5 July, due 7 August 2026; 6 July to 5 October, due 7 November 2026; 6 October to 5 January, due 7 February 2027; and 6 January to 5 April, due 7 May 2027. A quarterly update is a report, not a payment. Tax is still paid on 31 January and 31 July, and you still file a final return by 31 January 2028.
A quarterly reserve fits naturally alongside the updates: when you send one, the quarter's income and costs are already in front of you, so it is the obvious moment to top up the tax account.
A seasonal business: setting aside quarter by quarter
| Quarter | Profit in the quarter | Put aside | Update due |
|---|---|---|---|
| 6 April to 5 July | £9,000 | £2,083 | 7 August 2026 |
| 6 July to 5 October | £24,000 | £5,555 | 7 November 2026 |
| 6 October to 5 January | £18,000 | £4,167 | 7 February 2027 |
| 6 January to 5 April | £9,000 | £2,083 | 7 May 2027 |
A year's profit of £60,000 has a 2026/27 bill of £13,888.60 (23.1%), England, Wales or Northern Ireland. Each quarter's reserve is that share of the quarter's profit.
Four equal parts of £3,472.15 would over-save in the quiet first quarter and under-save in the busy second one. Matching the reserve to each quarter's profit keeps the account in step with the business; either way, it holds £13,888.60 by April.
Turnover, not profit, decides whether you are in. A sole trader with £58,000 of sales and £17,000 of costs has £41,000 of profit and a bill of £7,391.80, well within the basic-rate band, but £58,000 of qualifying income on the 2024/25 return means Making Tax Digital applied from April 2026.
Every figure here comes from the calculator above, using 2026/27 rates. Estimates for planning only, not tax advice.
Quarterly pitfalls
- Thinking a quarterly update means a quarterly tax payment. It does not; Self Assessment payment dates are unchanged.
- Ignoring late updates because there are no penalty points for 2026/27. All four updates must still be sent, and they are needed before you can file the return.
- Judging the threshold on profit. It is gross income from self-employment and property together.
- Relying on one estimate made in April. Recalculate the reserve after each quarter with the profit you actually made.
How much tax to put aside at each profit level
Divide the year's estimated bill by 12 or by 4. The percentage is the share of each pound of profit to move into a separate account.
| Yearly profit | Tax and NI | Set aside | A month | A quarter |
|---|---|---|---|---|
| £20,000 | £1,932 | 9.7% | £161 | £483 |
| £30,000 | £4,532 | 15.1% | £378 | £1,133 |
| £40,000 | £7,132 | 17.8% | £594 | £1,783 |
| £50,000 | £9,732 | 19.5% | £811 | £2,433 |
| £75,000 | £20,189 | 26.9% | £1,682 | £5,047 |
| £100,000 | £30,689 | 30.7% | £2,557 | £7,672 |
Your first bill can be up to 150% of this, because a payment on account for the next year may fall due at the same time.
Quarterly reserve — questions
Do sole traders pay tax every quarter?
Why use a quarterly reserve rather than monthly?
How does the quarterly figure relate to payments on account?
How often should I recalculate the quarterly reserve?
Where to go next
Official sources for this page
Calculator and worked examples checked against GOV.UK and HMRC rules on 3 November 2026.
Thinking of going limited? Compare first: with 2026/27 rates, a sole trader who takes all the profit out usually keeps more. If you already run a company, the Director's Pay & Tax Pack (£4.99) covers salary versus dividends, the director's loan account and year-end planning for 2026/27.