Self Assessment Tax Estimator
Estimate your 2026/27 Self Assessment bill and what's due on 31 January and 31 July.
Income less allowable expenses for 2026/27.
Salary before tax, from your P60.
The tax on your P60.
Rent less allowable expenses, before mortgage interest.
Earns a 20% tax credit under Section 24.
What you paid in, before your provider adds 20% (relief at source).
Leave at £0 if this is your first year with a bill.
When it's due
| 31 January 2028 | |
|---|---|
| Self Assessment bill for 2026/27 | £7,651.80 |
| First payment on account for 2027/28 (50% of £7,651.80) | £3,825.90 |
| Due 31 January 2028 | £11,477.70 |
| 31 July 2028 | |
| Second payment on account for 2027/28 | £3,825.90 |
Payments on account are due because the bill is £1,000 or more and 80% or less of the tax was collected at source. Each is half the bill, with any odd penny on the second.
How the bill is worked out
| Income | |
|---|---|
| Self-employed profit | £42,000.00 |
| Total income | £42,000.00 |
| Income tax | |
| Personal allowance | £12,570.00 |
| £29,430 of income at 20% | £5,886.00 |
| Income tax | £5,886.00 |
| Class 4 National Insurance (6%, then 2% above £50,270) | £1,765.80 |
| Tax for 2026/27 | £7,651.80 |
| Self Assessment bill for 2026/27 | £7,651.80 |
- Tax year 2026/27, England. Personal allowance £12,570, reduced by £1 for every £2 of income over £100,000.
- Income tax 20%, 40% and 45%; dividends 10.75%, 35.75% and 39.35% with a £500 allowance.
- Class 4 National Insurance 6% on profit between £12,570 and £50,270, and 2% above.
- Section 24 credit of 20% on the lowest of finance costs, rental profit and income above the personal allowance.
- Relief-at-source pension contributions extend the basic and higher rate bands by the gross amount.
- Scottish income tax rates, savings interest, capital gains and student loan repayments.
- Class 2 National Insurance, which is voluntary.
- The High Income Child Benefit Charge, Marriage Allowance and Gift Aid.
- Tax on employment income collected through your tax code for earlier years.
- Claims to reduce payments on account, and interest on late payment.
What it does
Add self-employed profit, salary, dividends, rent, mortgage interest and pension contributions. It works out the bill, whether payments on account apply, and what to pay on each date, with the working shown.
Read the guide behind itAn estimate is useful. Running it against your real accounts is better, and takes about ten minutes.