JoltMile HelpHMRC & tax

How JoltMile estimates your tax

Income tax and Class 4 National Insurance on your running profit, using the 2026/27 bands.

By JoltMilePublished 19/08/2026Updated 29/09/20262 min read
A Self Assessment summary listing turnover, mileage allowance, taxable profit and the estimated tax and National Insurance owed.

Last checked 12/09/2026.

What it is

A running estimate of the income tax and National Insurance you will owe on your delivery profit, updated with every shift so you can set the money aside as you go.

How it is calculated

Profit first: turnover, minus your mileage allowance, minus allowable expenses. Then:

  • Income tax. 20% on profit above your personal allowance of £12,570, 40% above £50,270, 45% at the top. The personal allowance tapers away above £100,000.
  • Class 4 National Insurance. 6% on profit between £12,570 and £50,270, then 2%.

Class 2 National Insurance is deliberately not in the total. Compulsory Class 2 was abolished from 6 April 2024: above £7,105 of profit it is treated as paid, and below it, it is voluntary at £3.65 a week. Including it would overstate what you owe. JoltMile shows it separately as guidance if your profit is below the threshold.

Tax is attributed to shifts incrementally - each shift is charged the difference its profit makes to the running total - so an early shift in the year, sheltered by your personal allowance, carries no tax while a later one does. That is what makes the per-shift hourly rate meaningful across a year.

Other income and PAYE

Add a job, rent or another trade under Other income and the estimate works out tax on all of it together, the way HMRC does. A job normally uses up your personal allowance first, so more of your driving profit becomes taxable, and the estimate shows that.

For a job, enter the tax already taken off each payslip. It comes off the bill at the end, so the tax on your wages is not counted as owed a second time. If more was taken than the whole year works out at, the estimate goes below zero, which means HMRC owes you. See other income and PAYE.

Only switch it off if you would rather not enter the job at all. Your driving profit is then taxed from the first pound, which is roughly right, but the estimate has no way to show the tax your employer already paid.

Mistakes to avoid

  • Treating it as your tax bill. It is an estimate for budgeting, and JoltMile does not file anything.
  • Forgetting payments on account (opens in a new tab) if your bill reaches £1,000.
  • Having a job and leaving it out. Add it under Other income, or the estimate assumes your driving is all you earn.
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