Best self-employed tax calculator
| Feature | LedgerKit | Money Worked Out | Sole Trader Tools | Freelance Tax UK |
|---|---|---|---|---|
| Class 4 National Insurance on profit | Yes | Yes | Yes | Yes |
| Employment income alongside profit | Yes | Yes | Yes | No |
| Calculated payments on account | Yes | No | No | No |
| Scottish income tax | Yes | Yes | No | No |
| Adverts | Not checked | No | Yes | Not checked |
| Third-party scripts | 1 found | None | 3 found | None |
| Cookie banner | Yes | No | Yes | Yes |
| Full written tax and NI working | Yes | No | No | No |
| Tax year shown | 2026/27 | 2026/27 | 2026/27 | 2026/27 |
| Income Tax plus Class 4 NI on £35,000 profit | £5,831.80 | £5,831.80 | £5,832 | £5,832 |
A tax bill can arrive long after a client pays you. If you also have a job, an estimate needs both incomes so you can judge how much profit to keep back.
How the four forms compare
Full working means Income Tax and Class 4 National Insurance (NI) bases and rates written out with figures. LedgerKit showed these. Money Worked Out's 'No' in this row means partial working; its income-tax difference and NI total still appear.
The annual row uses profit after costs in England, Wales or Northern Ireland, without job income, loans, pensions, dividends or other income. It excludes advance payments. Whole-pound displays round the reference. This row cannot certify a complete Self Assessment bill or mixed-income, Scottish and loan calculations.
Enter the income the form expects
Profit is turnover less allowable costs. Enter profit after those costs in Money Worked Out. Sole Trader Tools pairs profit with other income; Freelance Tax UK's only inputs are turnover and costs. LedgerKit accepts pay before deductions under other non-savings income. Job income affects the Income Tax bands profit reaches. Check the National Insurance rates alongside your tax estimate.
Keep advance payments separate from monthly saving
LedgerKit calculates possible payments on account, advance instalments towards the next bill, usually based on the previous bill. Money Worked Out's monthly set-aside includes Class 4 and the extra tax profit adds to job income, plus repayments for the selected loan. It does not calculate payments on account or deduct advances already paid. A monthly saving estimate alone does not show when an advance payment falls due. Your HMRC account gives the actual amounts.
What the dated checks establish
Source review and repeated input changes support the recorded features. Changing LedgerKit's income input also changed its advance estimates. Script counts group successfully loaded external JavaScript by service before consent; zero describes that capture only. LedgerKit loaded Cloudflare Web Analytics. Sole Trader Tools loaded Google Analytics, Google advertising scripts and Funding Choices. Cookie notices stayed unaccepted during the external checks, so normal use after consent remains untested. The calculation and rounding guide explains Money Worked Out's calculations.
How we checked
Four criteria were fixed before fresh control checks: Class 4 on profit, employment income alongside profit, calculated payments on account and Scottish income tax. Four chosen free forms were checked in an actual browser on 3 October 2026. LedgerKit payment amounts changed when turnover changed; its Scottish region and other-income controls changed the result. A warning or static example does not earn the calculated-payment feature. Full working means tax and Class 4 bases/rates written with figures; partial totals remain partial. Only the simple no-job/no-loan annual tax-plus-Class4 scenario is recorded in the numerical row; mixed-income, Scottish and student-loan correctness is not certified by those control checks. Script counts group successfully loaded external JavaScript by service before consent, including libraries but excluding CSS/fonts and separate beacon requests. Unknown adverts/cookies stay Not checked. External controls were checked while notices stayed unaccepted, so these checks do not establish normal usability.
Checked 3 October 2026: £35,000 sole-trader profit after expenses, England/Wales/Northern Ireland, no job income, student loan, pension, dividends or other income. This is the annual Income Tax and Class 4 amount, excluding payments on account. The sourced reference is £5,831.80. Whole-pound displays round to £5,832. This narrow check does not certify a complete Self Assessment bill.
Checked on 3 October 2026.
Which form supports Scotland?
LedgerKit and Money Worked Out have Scottish controls. Sole Trader Tools has none; Freelance Tax UK covers the rest of the UK.
Can I include a student loan?
LedgerKit excludes loans. Money Worked Out lets you choose an undergraduate plan or postgraduate loan, with one option active. Check your repayment plan before using the estimate. Loans belong in balancing payments; payments on account exclude them.
Does Class 4 cover my job's National Insurance?
Class 4 applies to profit under the GOV.UK rules. LedgerKit excludes employee and employer NI; use take-home pay for your job.
Will Freelance Tax UK's payment example track my inputs?
Its lower worked example stays fixed when turnover or costs change. The main tax result changes, so the example cannot supply your advance-payment estimate.