UK National Insurance Calculator 2024-25
Calculate your UK National Insurance contributions for 2024/25. Covers Class 1 employee NI and Class 2/4 self-employed NI with accurate rates.
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How to use this calculator
- 1
Enter your annual gross income (if employed) or taxable profits (if self-employed).
- 2
Select whether you are an employee or self-employed — the NI classes and rates are different.
- 3
Employees pay Class 1 NI deducted via PAYE; self-employed pay Class 2 (flat weekly rate) and Class 4 (profit-based).
- 4
The results show your annual, monthly, and weekly NI along with the effective rate.
- 5
NI contributions also build your qualifying years towards the State Pension — you need 35 qualifying years for the full new State Pension.
Frequently asked questions
What method does this tool use for employees?
It takes the annual figure you enter, charges 8% on the slice between £12,570 and £50,270 and 2% on anything above £50,270, and shows nothing for income at or below £12,570. Monthly is the annual amount divided by 12 and weekly is divided by 52. These are the 2024/25 figures built into this tool.
How does the self-employed option work?
It adds a Class 2 charge of £3.45 a week for 52 weeks (£179.40) whenever profits exceed £12,570, plus Class 4 at 6% on profits between £12,570 and £50,270 and 2% above. Whether Class 2 is actually payable, treated as paid or purely voluntary for a given profit level depends on rules that have changed over time, so check HMRC before relying on the Class 2 line.
Are these the current rates?
They are the ones labelled 2024/25 in the tool. UK National Insurance rates and thresholds change at least every tax year on 6 April, the tool’s tables are not updated automatically, and HMRC or a qualified adviser governs what applies to you. If you are looking at another year, the output may not match.
Why might my payslip show a different figure?
Payroll applies thresholds per pay period (weekly or monthly), so uneven pay across the year can produce a different total from one annual calculation. Directors have special rules, category letters change the rates for some people, and the tool ignores employer contributions, deferment and contracted-out arrangements.
Does the tool include employer National Insurance?
No. Only the employee’s share is calculated, and that share is the only thing deducted from pay in this tool. Employer contributions are a separate cost to the employer and are not modelled.
Does it handle National Insurance after State Pension age?
No. The tool does not ask your age, and applies the same charges at every age. People over State Pension age may have different obligations, so check HMRC.
What happens with low or zero income?
At or below £12,570 every NI line shows £0, and the effective rate shows 0.0%. A negative amount is treated as zero, and an emptied box is already zero. An exact figure of £12,570 for a self-employed person also produces £0, because both Class 2 and Class 4 are triggered only by profits above it.
Does it say anything about State Pension or voluntary contributions?
No. The tool does not model qualifying years, credits, Class 3 voluntary contributions or any benefit entitlement. It only reports the amount of each charge for the figures entered.
UK National Insurance: how this calculator charges employees and the self-employed
How the employee charge is built
For employees the tool treats the annual income you enter as one slice of earnings. Nothing is charged up to £12,570; between £12,570 and £50,270 each pound attracts 8%; above £50,270 each pound attracts 2%. The weekly and monthly lines are simply the annual amount divided by 52 and by 12, and the effective rate is the annual charge divided by income. The thresholds and rates are the 2024/25 figures built into this tool, applied annually and not per pay period.
How the self-employed charge is built
For the self-employed option the tool adds two parts. Class 2 is a flat £3.45 a week for 52 weeks, £179.40 in total, and appears whenever profit is above £12,570. Class 4 is 6% on profit between £12,570 and £50,270 and 2% above. Whether Class 2 applies to a particular profit level in the year you are interested in is a question for HMRC; the tool simply applies this rule, which means its self-employed total includes the £179 whenever the threshold is passed.
Worked example: £40,000 employed and self-employed
An employee on £40,000 pays 8% of the £27,430 above £12,570, which the tool shows as £2,194 a year, £183 a month, £42.20 a week and an effective rate of 5.5%. A self-employed person with £40,000 of profit has £179 of Class 2 and £1,646 of Class 4, a total of £1,825, or £35.10 a week and 4.6% effective. The gap of £369 comes from the lower Class 4 rate less the Class 2 add-on.
Worked example: £60,000 across the upper limit
At £60,000 an employee pays 8% on £37,700 (£3,016) plus 2% on £9,730 (£195), a total of £3,211, or 5.4%. A self-employed person pays £179 of Class 2 plus £2,457 of Class 4, totalling £2,636, or 4.4%. The table lays these out with other incomes for comparison.
| Income or profit | Employee total | Self-employed Class 2 | Self-employed Class 4 | Self-employed total |
|---|---|---|---|---|
| £20,000 | £594 | £179 | £446 | £625 |
| £40,000 | £2,194 | £179 | £1,646 | £1,825 |
| £50,270 | £3,016 | £179 | £2,262 | £2,441 |
| £60,000 | £3,211 | £179 | £2,457 | £2,636 |
| £100,000 | £4,011 | £179 | £3,257 | £3,436 |
What the tool does not model
Employer contributions, deferment, category letters, directors’ annual earnings rules and age-related exemptions are not part of the calculation. Voluntary Class 3 contributions, credits and State Pension forecasts are also outside it. Because UK thresholds and rates change at least every 6 April and the tool is not updated automatically, treat the output as an estimate and check HMRC for the year you need.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →