Quick answer: As a rough guide, self-employed people set aside 25–30% of their profit for Income Tax and National Insurance ,but the accurate figure depends on your personal allowance, tax band and payments on account, so a real-time estimate based on your actual numbers is far safer than a flat percentage.
The single biggest cause of January panic is not setting enough aside through the year. Here’s how to estimate it properly.
What’s the rule of thumb for tax to set aside?
Many sole traders set aside 25–30% of profit to cover Income Tax and National Insurance. It’s a reasonable starting point, but it ignores your personal allowance, your tax band and any payments on account ,so it’s often wrong in both directions.
Why do flat percentages mislead?
- If your profit is low, you may pay far less than 30% after your personal allowance.
- If you’re a higher-rate taxpayer, 30% won’t be enough.
- Payments on account can mean you pay 150% of your bill in a single January if you don’t plan for them ,a nasty surprise for first-timers.
What actually determines your tax bill?
Your tax depends on total profit, allowable expenses, your personal allowance, your tax band and your National Insurance position. The only accurate “set aside” figure is one calculated from your real numbers. Make sure you’re claiming everything first ,see allowable expenses for the self-employed ,because every expense you miss is tax you needn’t pay.
What’s the real-time alternative to guessing?
Instead of guessing a percentage, CleanBooks AI keeps a live tax estimate based on your actual income and expenses, and even suggests a monthly set-aside amount to cover the full year. As your confirmed quarters come in, the estimate sharpens. That turns “I hope I’ve saved enough” into a number you can trust. Read real-time tax estimates for how it works, and real-time cash flow forecasting for keeping that money available when the bill lands.
Does MTD make this easier?
Yes. Because MTD has you reporting quarterly, your position is always current ,no more discovering the damage in January. See how the new system compares in Self Assessment vs MTD and the smooth path across in Self Assessment to MTD transition.
Know your number, not a guess. Get a live tax estimate with CleanBooks AI.
