Sole Trader Tax Calculator 2026/27: Tax, NI & MTD Check

By Marina Jahan · Reviewed by Shamayun Chowdhury, ACMA · Tax year 2026/27 · Last reviewed October 2026

January is when most self-employed people discover their tax bill, and by that point the number can’t be changed, only paid. Run your figures through a sole trader tax calculator a few months earlier and the same bill becomes something you’ve budgeted for, a little at a time, instead of a shock.

Our free tool below gives you an estimate of Income Tax and Class 4 National Insurance on your self-employed profit for 2026/27. It handles both the Scottish bands and those used in England, Wales and Northern Ireland, and it tells you whether Making Tax Digital is likely to catch you, a question answered by turnover rather than profit.

Sole trader tax calculator for 2026/27

Fill in the boxes for the tax year that began on 6 April 2026 and ends on 5 April 2027. The sums run inside your own browser, so the figures you enter never leave your device.

Filling in the four boxes

1. Turnover: the total your business earned in the year, before deducting anything.
2. Expenses: allowable running costs such as stock, fuel, phone bills and insurance. Costs under £1,000? Tick the trading allowance option and leave this box alone.
3. Other taxable income: wages or a pension count here, because they fill the lower bands before your business profit does.
4. Location: pick Scotland if you live there and the Scottish bands are applied for you.

The calculator’s rates match GOV.UK’s published Income Tax bands and its page on National Insurance for the self-employed. Use this sole trader calculator for planning; the final figure comes from HMRC once your return is processed. If you’re unsure whether turnover puts you into Making Tax Digital, our MTD thresholds guide sets out each stage.

Inside the sole trader tax calculator: how your bill is built

The sole trader tax calculator does nothing clever. It repeats, in order, the sums HMRC carries out on your return, which means you can check any result yourself, whatever tool or adviser produced it.

Calculate sole trader tax in four steps

1. Start with profit. Turnover for the year minus allowable expenses. Sales alone are never the taxable figure.
2. Take off the Personal Allowance. Total income up to £12,570 carries no Income Tax. The allowance shrinks once income passes £100,000, losing £1 for each £2 above that, and is gone by £125,140.
3. Apply the bands. Each portion of what remains is taxed at the rate for its band. Wages or a pension sit in the bottom bands first, so business profit can begin in a higher one.
4. Add Class 4. This National Insurance looks only at self-employed profit; a salary never affects it.

The 2026/27 bands

One set of bands covers England, Wales and Northern Ireland, and the thresholds are frozen for several more years.

Scotland sets its own rates on earnings and trading profit. According to mygov.scot’s 2026/27 table, they are:

Class 4 now, and why Class 2 has gone

Wherever you live in the UK, Class 4 is charged at 6% between £12,570 and £50,270 of profit and 2% on the rest. It’s settled through Self Assessment rather than billed separately. A good sole trader tax calculator shows it on its own line, so you can see how much of the total is National Insurance and how much is Income Tax.

Class 2 trips up a lot of older tools. Nobody self-employed has been obliged to pay it since April 2024. Profit of £7,105 or more earns you a qualifying State Pension year at no cost, and if you fall short of that you have the option of a voluntary £3.65 a week in 2026/27. Any tax calculator sole trader readers come across that still adds a weekly Class 2 charge, or uses 8% or 9% for Class 4, is working from old rules.

Real costs or the £1,000 allowance?

You deduct one or the other: actual allowable expenses, or the £1,000 trading allowance, never both. If your genuine costs exceed £1,000, claiming them gives the smaller bill, and switching the checkbox on and off in the sole trader tax calculator shows the gap straight away. The allowance tends to suit small sidelines with very few costs. Good records matter either way, as our guide to digital record keeping explains.

£50,000 profit after tax: a sole trader example

Put Amara’s turnover and costs into the sole trader tax calculator UK users can try at the top of this page and the same figures appear in a moment. More usefully, she can see how a new camera or a quieter few months would change the outcome before either happens.

What sole traders pay at different profits

For a quick reference, here’s what the sole trader tax calculator returns for a range of 2026/27 profits, with no salary, pension or student loan in the mix. Amounts are rounded to whole pounds.

Scottish sole traders come out slightly ahead up to roughly £33,500 of profit. Past that point they pay more, and the difference grows fast once the 42% rate applies.

Where a tax calculator for sole traders falls short

Our sole trader tax calculator, like any other, can only work with what you type in. Several things alter the real bill without appearing in a quick estimate:

• Advance payments. When a year’s bill tops £1,000, HMRC normally wants half of the following year’s tax up front, split between January and July. GOV.UK’s page on payments on account covers the detail, and our guide to paying Self Assessment explains how to send the money.
• Income between £100,000 and £125,140. Here each extra pound also strips 50p from the Personal Allowance, so with Class 4 added the slice is taxed at about 62%. The taper is set out on HMRC’s income over £100,000 page.
• Student loans, pension contributions and Gift Aid. Loan repayments are collected through your return, while personal pension payments and Gift Aid widen the basic-rate band.
• Capital allowances and past losses. Equipment or a vehicle bought for the business, or losses carried forward, can cut taxable profit well below the figure in your accounts.

Profit, turnover and Making Tax Digital

Profit decides your tax. Making Tax Digital looks at something different: qualifying income, which is gross self-employed turnover plus gross rent, with no expenses taken off. So the sole trader tax calculator tests MTD against what you enter as turnover, not against profit.

Go back to Amara. Her £50,000 profit seems to sit right on the line, but her £61,000 of turnover is the figure that matters. If her 2024/25 return looked similar, MTD for Income Tax has applied to her since 6 April 2026, with quarterly updates sent from software. Someone with £35,000 turnover and slim margins is still brought in from April 2027. The sole trader MTD rules explain where you stand.

Errors that skew the estimate

Entering sales as profit. Typing your turnover into a profit box can roughly double the result. Take costs off first, or use the sole trader tax calculator’s separate boxes for turnover and expenses.

Relying on old rates. Tools that still use 8% or 9% for Class 4, or add a compulsory Class 2 charge, overstate what you owe. Look for the tax year and the rates on any sole trader tax UK calculator before trusting its answer.

Ignoring the January jump. The estimate covers a single year. Your first January bill can be 50% higher once the opening payment on account is added.

Paying Class 2 unnecessarily. Profit above £7,105 already protects your State Pension year, so there’s no need to pay anything extra.

Your questions answered

How much tax does a sole trader pay in 2026/27?

Nothing on the first £12,570 of profit. After that, 20% Income Tax and 6% Class 4 National Insurance apply up to £50,270, then 40% and 2% above it. In England, £30,000 of profit means a combined bill of about £4,532.

How much tax will I pay? Sole trader also on PAYE

Wages use up your Personal Allowance and lower bands before your business profit does, so more of the profit may be taxed at 20% or 40%. Enter wages under “Other taxable income” and the sole trader tax calculator takes them into account. Class 4 is still based only on your business profit.

Is a sole trader tax calculator accurate?

For the figures you give it and the 2026/27 rates, yes, but treat the result as an estimate. Capital allowances, losses, pension payments and student loans can all move the real bill, which HMRC works out from your return.

Is Class 2 National Insurance still due from sole traders?

No longer compulsory. The charge ended for everyone self-employed in April 2024. If profit is under £7,105, you can choose to pay £3.65 a week to keep your State Pension record intact.

Should I enter profit or turnover?

Type turnover and costs into their own boxes; the sole trader tax calculator then works out profit for you. Tax is based on profit, but turnover decides whether Making Tax Digital applies.

What share of profit should I put aside for tax?

Around 26% of profit above £12,570 while you’re a basic-rate taxpayer is a sensible starting point, with extra for payments on account from year two. Use the monthly amount the sole trader tax calculator shows as your standing order.

Will MTD increase my tax bill?

No. It changes record keeping and reporting, with quarterly updates from software, but not the rates or the 31 January payment date.

Can Scottish sole traders use the sole trader tax calculator?

It does. Choose Scotland under “Where you live” and the six Scottish bands are used. Class 4 National Insurance is identical across the UK.

Final verdict: making a sole trader tax calculator work for you

Used early and regularly, a sole trader tax calculator turns January from a guessing game into a planned payment. Keep turnover and costs apart, check the rates belong to 2026/27, allow for payments on account and test turnover against the MTD stages. Saving the monthly figure as you go means the money is ready when HMRC asks.