Bonus Tax and NI Calculator
Estimate how much of your bonus you may keep after UK income tax and employee National Insurance. Enter your annual salary, planned bonus, region and optional salary sacrifice to see the gross bonus, tax on the bonus, NI on the bonus and estimated net payout.
Calculate your bonus take-home pay
Expert guide to using a bonus tax and NI calculator
A bonus can feel exciting right up until you see the payslip. Many employees expect a bonus to be taxed at a special penalty rate, but in most UK cases that is not actually what is happening. Instead, the bonus is added to your earnings and taxed according to the same income tax rules that apply to salary. The reason the deduction looks heavy is simple: a bonus often lands on top of income that has already used up lower tax bands, so much of the extra amount is taxed at your highest marginal rate. A good bonus tax and NI calculator helps you estimate that impact before payroll runs.
This calculator is designed as a practical planning tool for UK employees. You enter your annual salary, your gross bonus, the tax region that applies to you, and any salary sacrifice or pre-tax pension amount that reduces taxable earnings. The tool then compares your estimated total annual deductions with and without the bonus. That difference is the most useful number for planning because it isolates the tax and employee National Insurance attributable to the bonus itself.
Quick rule of thumb: your bonus is usually taxed at your marginal rate, not a separate bonus rate. If your salary already places you in a higher band, a large part of your bonus may be taxed at 40% or 45% for income tax, with NI added on top.
How bonus taxation works in practice
In the UK, a cash bonus paid through payroll is normally treated as employment income. That means it can trigger:
- Income tax under PAYE
- Employee National Insurance contributions
- Possibly student loan deductions if you are above the relevant threshold
- Potential loss of personal allowance if income exceeds £100,000
The key concept is that payroll does not ask whether money is “salary” or “bonus” in any emotional sense. It just looks at taxable pay. If your annual salary is £45,000 and you receive a £5,000 bonus, your taxable pay becomes broadly equivalent to £50,000 before any allowances or pre-tax deductions. That can push part of the bonus into a higher tax bracket or closer to the point where NI rates change.
Why your bonus may look overtaxed on a payslip
Employees often say their bonus has been “taxed at 50%” or something similar. Usually the explanation is one of the following:
- Marginal rate effect: your lower-rate tax band may already be used up by salary.
- NI on top of income tax: people remember the total deduction but mentally label all of it as tax.
- Student loan deductions: these can materially reduce the amount that arrives in your bank account.
- Cumulative payroll adjustments: PAYE may reconcile earlier underpayments or overpayments during the year.
- Tax code issues: an emergency code or restricted allowance can temporarily increase deductions.
That is exactly why a bonus tax and NI calculator is useful. It separates the moving parts and gives you a structured estimate. You can then compare that estimate with your payslip and identify whether the result seems reasonable.
Official 2024/25 thresholds that matter for a bonus
For most users, the most important official figures are the personal allowance, the higher-rate threshold and the NI thresholds. The table below summarises core 2024/25 numbers that commonly drive the result.
| Measure | England, Wales and Northern Ireland | Scotland | Why it matters for a bonus |
|---|---|---|---|
| Personal Allowance | £12,570 | £12,570 | The first slice of income is generally tax free unless your allowance is tapered away. |
| Personal Allowance taper starts | £100,000 | £100,000 | Allowance reduces by £1 for every £2 of income above this level, increasing the effective tax cost of a bonus. |
| Higher-rate threshold | £50,270 | Scottish higher rate starts at £43,663 | A bonus can push some or all of the extra income into a higher tax band. |
| Additional or top rate threshold | £125,140 | Top rate above £125,140 | Larger bonuses at higher incomes can be taxed at the highest rates. |
| Employee NI primary threshold | £12,570 | £12,570 | Employee NI generally starts above this level. |
| Employee NI upper earnings limit | £50,270 | £50,270 | Employee NI is usually 8% between the threshold and this limit, then 2% above it for standard employees. |
These figures are the foundation of any sensible estimate. If your base salary is already above the higher-rate threshold, then a new bonus is likely to suffer higher-rate tax immediately. If your total income moves above £100,000, the bonus can become even more expensive because your personal allowance starts to shrink. That creates an effective marginal tax rate that can be much higher than many employees expect.
Comparison of tax bands for 2024/25
The next table shows the headline income tax rates most relevant when estimating a bonus. Scotland has a different structure for non-savings, non-dividend income, which means the same bonus can produce a different result depending on where you are taxed.
| Jurisdiction | Band | Rate | Published threshold statistic |
|---|---|---|---|
| England, Wales and Northern Ireland | Basic rate | 20% | Taxable income above the personal allowance up to £50,270 total income |
| England, Wales and Northern Ireland | Higher rate | 40% | Total income from £50,271 to £125,140 |
| England, Wales and Northern Ireland | Additional rate | 45% | Total income above £125,140 |
| Scotland | Starter / Basic / Intermediate | 19% / 20% / 21% | Applies across lower and middle Scottish bands up to £43,662 total income |
| Scotland | Higher / Advanced / Top | 42% / 45% / 48% | Higher starts at £43,663 and top rate applies above £125,140 |
What this calculator includes
This page estimates the incremental cost of your bonus by comparing annual deductions before and after the bonus is added. It includes:
- Income tax using 2024/25 rates
- Employee National Insurance using standard employee annual thresholds
- Optional student loan deductions for selected plans
- Personal allowance taper above £100,000
- An estimated net bonus result and visual chart
That methodology is especially useful because it mirrors the real question most people ask: “If I get this bonus, how much more tax and NI will I pay because of it?” The answer is not the total tax for the year. It is the difference between the annual deductions on your compensation package without the bonus and with the bonus.
What this calculator does not cover perfectly
No online tool can replace your employer’s exact payroll setup. This is still an estimate, and some payslips will differ. Common reasons include:
- Non-standard National Insurance category letters
- Director NI calculations
- Monthly cumulative payroll nuances
- Benefits in kind and tax code adjustments
- Bonus deferral into pension, shares or other structured reward arrangements
- Scottish taxpayer status changing during the year
If your actual payslip is materially different from this estimate, check your tax code and NI category first. Then review whether student loan, pension salary sacrifice, taxable benefits or previous payroll corrections are involved.
How to use the result for better planning
Once you know the approximate net amount, you can make much better decisions. For example, if a bonus pushes you through a threshold, salary sacrifice into pension may be worth exploring. This can reduce taxable pay and sometimes NI-able pay, improving the effective value of the reward. It may also help protect your personal allowance if your total income is near £100,000.
Here are a few smart planning questions to ask after using the calculator:
- Would increasing pension salary sacrifice reduce my marginal tax exposure?
- Am I close to £50,270, £100,000 or £125,140 where the effective cost of extra income can rise sharply?
- Do I have student loan deductions that make the net bonus materially lower than expected?
- Is the bonus contractual cash, or could part of it be taken in a more tax-efficient way if my employer offers alternatives?
Worked example
Suppose your annual salary is £45,000 and you expect a £5,000 bonus. In broad terms, most of your salary is already sitting inside the basic-rate band. The bonus may therefore partly use the remaining basic-rate space and possibly push the top slice toward the higher-rate threshold, depending on your exact taxable pay and pension deductions. Employee NI may also apply at 8% on the part below the upper earnings limit, and at 2% above that level. If you also repay a student loan, your final banked amount can be lower than expected even though the bonus itself has not been subject to any special bonus tax rate.
That is why incremental modelling is so valuable. It focuses on the additional deductions caused by the bonus rather than trying to interpret the whole payslip at once.
When a bonus can trigger a surprisingly high effective rate
There are two situations where employees are often shocked by the outcome:
- Crossing £100,000 total income: the personal allowance starts tapering away. That means each extra £1 can effectively suffer more than the headline rate because you are also losing tax-free allowance.
- Bonus plus student loan: a bonus can create a stack of deductions that includes income tax, NI and loan repayment, making the combined deduction feel severe.
For higher earners, a pension salary sacrifice arrangement can materially change the picture. While every situation is personal, it is often worth comparing the net cash bonus with the long-term value of increasing pension contributions.
Where to verify rates and thresholds
Always verify critical decisions against official sources, especially if your bonus is large. The following pages are good starting points:
- UK Government income tax rates and Personal Allowances
- UK Government National Insurance rates and category letters
- UK Government student finance and repayment information
Final takeaway
A bonus tax and NI calculator is most useful when it helps you understand marginal deductions. Your bonus is typically not being singled out for punishment. It is simply being layered on top of your existing earnings, often after lower tax bands have already been used. By estimating income tax, employee NI and optional student loan deductions together, you get a much clearer view of what your bonus may actually add to your take-home pay. Use the calculator above as a planning tool, compare the estimate with your payslip, and check official guidance for any large or high-stakes decisions.