Best Tax Set-Aside Calculator UK (2026)

Updated July 2026 · Independent comparison, not sponsored

Knowing how much to save for your tax bill is one of the most useful numbers a sole trader can have. Here's how the main ways to work it out compare.

	PayToolkit	FreeAgent	GoSimpleTax	DIY Spreadsheet
Free	✓	Free with certain banks	Paid	✓
No signup	✓	✗	✗	N/A
Instant estimate	✓	✓	✓	✗
Includes Payments on Account	✓	✓	✓	Manual
Connects to expense tracking	✓	✓	✓	✗
Monthly set-aside target	✓	Limited	Limited	Manual

Full accounting platforms like FreeAgent and GoSimpleTax calculate a running tax estimate as part of a much bigger toolset, but usually require a subscription or a specific bank account to access for free. A spreadsheet works but takes manual upkeep. PayToolkit's Tax Set-Aside Calculator gives you the same core number — instantly, with no signup — and links directly into the free Tax Dashboard if you want it tracked automatically as you log income and expenses.

Calculate my set-aside amount

FAQ

How accurate is a tax set-aside estimate?

It's an estimate based on your profit and current Income Tax and NIC bands. Your actual bill can vary based on other income, allowances, and deductions, so treat it as a guide rather than a final figure.

Does this include Payments on Account?

Yes — PayToolkit's calculator factors in that HMRC may require Payments on Account if your bill is over £1,000, so your set-aside target reflects the fuller picture.

Methodology: Comparisons are based on each provider's own published pricing and feature pages as of July 2026. We link out to alternatives fairly and do not accept payment for placement in this comparison. If something here looks out of date, let us know.