UK Tax Savings Pot Calculator
Estimate how much to put aside each month for the January Self Assessment payment linked to the tax year you select, based on projected sole-trader income, tax already deducted and what you have saved.
LedgerKit provides estimates based on the information entered and the configured rates. Results do not constitute accounting, tax or legal advice. Check the latest official guidance or consult a qualified professional before acting on a calculation.
How this calculator works
Enter your full-year turnover and deduct either forecast allowable business expenses or the Trading Allowance. Add other income because it can change the Income Tax rates and Personal Allowance applied to your business profit.
The calculator estimates Income Tax and Class 4 National Insurance using the same method as the Self-Employed Tax Calculator. It then subtracts full-year PAYE or CIS tax expected and payments on account already paid or funded separately.
The January target combines the remaining current-year position with any possible first payment on account. Money already in your tax savings pot is deducted, and the shortfall is divided by the monthly transfers left. The monthly amount is rounded up to the next penny.
A possible second payment on account due in July is shown separately and is not included in the January savings target. Payments on account are advance payments towards the following tax year, not extra tax.
This is a planning estimate for one UK-resident sole trader. It does not include trade losses, capital allowances, basis-period adjustments, student loans, the High Income Child Benefit Charge, Capital Gains Tax, savings income, specialist reliefs or the annual National Insurance maximum.
Worked example
For 2026/27 in England, £50,000 turnover less £10,000 allowable expenses gives £40,000 taxable profit. Estimated annual Income Tax and Class 4 National Insurance is £7,131.80. A possible first payment on account of £3,565.90 makes the January target £10,697.70. With £2,000 already saved and 10 monthly transfers left, the monthly amount is £869.77. A possible £3,565.90 July payment is shown separately.
Frequently asked questions
Does this calculator move money into a savings pot?
No. It only estimates an amount. It does not create an account, move money or contact HMRC.
What does the monthly amount cover?
It covers the estimated current-year balance and any first payment on account indicated for January, less the amount already saved. A possible second payment on account due in July is not included.
Are payments on account extra tax?
No. They are advance payments towards the next tax year. They are normally paid in two instalments, and the actual amounts can change when the next return is completed.
Why is the possible July payment not included?
This calculator keeps the January target clear. It shows a possible second payment on account separately so you can plan for that later date as well.
Should I enter PAYE and CIS deductions?
Yes. Enter the full-year Income Tax and CIS deductions expected for the selected tax year under more tax and payment details. For payments on account, include only amounts already paid or funded outside this monthly plan.
What counts as money already saved?
Include only money ring-fenced and available for this Self Assessment payment. Do not include unpaid invoices, available credit or amounts already paid to HMRC.
What if the estimate shows an overpayment?
Choose whether to treat it as credit left on the HMRC account or a refund. If it is refunded and you ring-fence that money, include it in the savings pot; do not also treat it as HMRC credit.
What if my income or costs change?
Recalculate using your latest full-year forecast and the number of transfers still available. The estimate does not update after you leave the page.
Who should not rely on this estimate?
Do not use it as a final return calculation for a limited company, a partnership share, multiple trades, losses, a short or transitional basis period, someone affected by the annual National Insurance maximum, or a case involving specialist income, reliefs or charges.