Sole Trader Tax Planner 2026/27
Know exactly how much to set aside for tax, every month.
The Sole Trader Tax Planner turns your takings and costs into one simple monthly amount to save, so your Self Assessment bill never comes as a shock. It's built by GRJ Bookkeeping for UK sole traders and uses the rates for the 2026/27 tax year.
What it works out
- Income tax, including Scottish rates
- Class 4 National Insurance
- Student and postgraduate loan repayments
- Jobs alongside your business, with any tax code, including jobs you started or left during the year (P45 and payslip figures)
- P11D benefits and employment expenses
- CIS deductions for construction subcontractors, with likely refunds
- The High Income Child Benefit Charge, for you or your partner
- Personal pension payments
- Payments on account, with every payment date and amount
How it helps
- One clear monthly amount to move into your tax pot
- Shows whether you're on track or need to top up
- Warns you about January's payments on account, which catch out many people in their first year
- Shows every step of the calculation, so you or your accountant can check it
Use it as an app or a spreadsheet
- The app opens in your web browser on a laptop or desktop. No sign-up, no subscription, and it works offline. Your figures stay on your computer.
- Prefer spreadsheets? The Excel version has the same calculations.
For the 2026/27 tax year only (6 April 2026 to 5 April 2027). Tax rates change every year.
This planner gives an estimate to help you budget. It isn't tax advice, and your final bill is worked out on your Self Assessment tax return.