SoleTraderTaxCalculator
Updated for 2026/27

Self Assessment calculator

Estimate what your next Self Assessment bill could look like. The monthly set-aside and quarterly reserve figures help you build the cash ahead of January and July payments.

Updated for 2026/27. Uses UK tax bands and HMRC/GOV.UK guidance. Estimates only — not tax advice.

Calculate sole trader tax Read the guides
Tax bill estimatePayments on accountMonthly reserveBudget planning
2026/27 tax year England, Scotland, Wales & NI Student loan support Practical reserve figure

Self Assessment calculator

Plan your Self Assessment bill and reserves — 2026/27

Adjust inputs below — results update instantly.

Tax year 2026/27
How do you earn?

Enter profit after allowable business expenses — not total turnover.

The annual profit used in calculations will be monthly profit × 12.

£
£
Expenses exceed estimated turnover — check your inputs.
£
£
Expenses exceed estimated turnover — check your inputs.
£
£
£36,568take-home / year£3,047/mo
Monthly net
£3,047
Tax set-aside
£703
Quarterly reserve (estimate)
£2,108
Take-home£36,568
Income Tax£6,486
National Insurance£1,946
Student loan£0
Pension£0
Show detailed breakdown ▼
Income tax£6,486.00
Class 4 National Insurance£1,945.80
Student loan£0.00
Pension contribution£0.00
Take-home after tax£36,568.20
Monthly tax set-aside£702.65
Share this result
HMRC 2026/27 · Methodology

Employed too, or a company director? Get all 7 tax packs in the Tax Pack Library — £9.99 

Payments on account

Your Self Assessment payment timeline

Based on your estimated bill of £0 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.

31 January
£0
Balancing payment £0 + first payment on account £0
31 July
£0
Second payment on account
Following 31 January
£0
Next balancing payment + first payment on account for the following year
Tax year
ends 5 Apr 31 Jan 31 Jul Next
31 Jan
Set aside each month (ongoing)
£0
Set aside in your first payment-on-account year
£0
Why your first Self Assessment payment can feel higher
The first time you owe £1,000 or more, your 31 January bill includes two things: the full tax bill for the year just finished (the "balancing payment"), plus your first payment on account towards the next year — normally half of this year's income tax and Class 4 NI. That combination is why the first January can feel like roughly 150% of the tax itself.
What payments on account are
Payments on account are advance payments towards your next Self Assessment bill. There are usually two — one due 31 January and one due 31 July — and each is normally half of your previous year's income tax and Class 4 National Insurance. (Class 2 NI, student loan repayments and Capital Gains Tax are not included in payments on account; they are paid in the balancing payment.)
When you might not need to make them
You normally do not make payments on account if your last Self Assessment bill (income tax and Class 4 NI) was under £1,000, or if more than 80% of the tax you owe was already collected at source (for example through PAYE). You may also be able to ask HMRC to reduce your payments on account if you expect your next bill to be lower — but reducing them too far can lead to interest, so check your figures carefully.
Why your exact HMRC bill may differ
This is an estimate based on the figures you entered. Your real Self Assessment bill depends on your full tax position, allowable expenses, other income, reliefs and any adjustments. Always check your actual figures in your HMRC online account before making a payment. This tool does not give personalised tax advice.
About this calculator

Planning for your Self Assessment payment

The 31 January deadline catches people unprepared when they have not built a cash reserve during the year. If your bill for 2026/27 exceeds £1,000, HMRC will also require payments on account in January and July — each equal to 50% of the prior year's bill. That effectively means paying 150% of one year's tax bill by the following January.

The monthly set-aside figure in this calculator helps you build steadily toward that total so the payment does not come as a shock. The quarterly reserve breaks it into four chunks for those who prefer quarterly financial reviews.

Last updated July 2026. Written and reviewed by James Whitfield against current GOV.UK and HMRC guidance. Estimates for planning only — not tax, accounting or financial advice.

Self Assessment planning — questions

When do I pay Self Assessment tax?
The main deadline is 31 January after the end of the tax year — so 31 January 2028 for 2026/27 tax. If your bill exceeds £1,000, you also pay a first payment on account by 31 January and a second by 31 July.
What are payments on account?
Payments on account are advance payments toward your next year's tax bill. HMRC requires them when your Self Assessment bill exceeds £1,000 and less than 80% of your tax is collected at source. Each payment is 50% of the prior year's bill.
How much should I have in reserve by December?
A solid rule of thumb: have your full estimated annual tax-plus-NI bill in reserve by 31 December. That covers the January deadline plus leaves room for the payments on account, which are added on top.
Self-Employed Tax Calculator UK
Estimate income tax, Class 4 National Insurance and take-home pay from self-employed income for 2026/27. Covers freelancers, contractors and sole traders.
Sole Trader Tax Calculator
Estimate sole trader income tax, Class 4 National Insurance and take-home profit for 2026/27.
Self Assessment Calculator UK
Estimate your Self Assessment tax bill from sole trader profit and plan for January and July payment deadlines.
Tax Set-Aside Calculator UK
Calculate how much to set aside each month from sole trader profit to cover income tax and National Insurance for 2026/27.
Take-Home Profit Calculator
Estimate how much of your sole trader profit remains after income tax, NI and optional deductions for 2026/27.
Self-Employed National Insurance Calculator 2026/27 (Class 4)
Class 4 NI for 2026/27: 6% on profit from £12,570 to £50,270, 2% above. £30,000 profit pays £1,045.80. Free sole trader NI calculator with band breakdown.
Sole Trader Expenses 2026/27: What You Can Claim and What It Saves
What sole traders can claim in 2026/27: the wholly-and-exclusively test, 55p mileage, home working, equipment. Each £1 claimed saves about 26p at basic rate.
Making Tax Digital for sole traders
What Making Tax Digital for Income Tax means in practice, who it affects, income thresholds, digital record requirements and how to prepare.
Payments on Account 2026/27: Dates, 150% First Bill, SA303
Payments on account are two 50% advances due 31 January and 31 July. Why the first January bill is 150%, the £1,000 and 80% exemptions, and reducing them with SA303.
Self Assessment deadlines for sole traders
The key filing and payment deadlines sole traders must know, what late filing costs, and how to use your tax estimate to prepare in advance.

Figures reviewed for the 2026/27 tax year (last updated July 2026). Source: GOV.UK.

Making Tax Digital

MTD for Income Tax

From 6 April 2026, Making Tax Digital for Income Tax is mandatory for sole traders and landlords with qualifying income over £50,000. That means keeping digital records and sending HMRC a short update every quarter through recognised software, instead of one Self Assessment at year end. The threshold drops to £30,000 in April 2027 and £20,000 in April 2028, and HMRC reckons around 860,000 people are in the first wave.

HMRC-recognised software includes FreeAgent, Xero, QuickBooks, Sage and Zoho Books. FreeAgent is free for Mettle and NatWest business banking customers. There are no penalties for late quarterly updates during 2026/27.

Getting set up

Business bank accounts

Keeping a separate account for business income and expenses makes Self Assessment and record-keeping considerably easier.

Starling Business
Permanently free, no monthly fee. A fully licensed UK bank - eligible deposits are FSCS protected up to £120,000 per eligible depositor, per authorised bank (brands sharing one banking licence share one limit). As a sole trader your business and personal accounts at the same bank count towards one £120,000 limit. Accepts sole traders and limited companies. 0.7% on Post Office cash deposits.
Open an account →
Tide
Free to open. Built-in invoicing and expense tracking. 20p per outgoing transfer on the free tier. Accepts businesses with no trading history. Funds are safeguarded as e-money, not FSCS protected.
Open an account →
Mettle by NatWest
Free for sole traders and single-director limited companies. Includes FreeAgent bookkeeping at no extra cost - useful for MTD record-keeping. Funds safeguarded as e-money, not FSCS protected. No cash deposits.
Open an account →

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.