Estimate your Class 1 NI contributions under the latest HMRC rates.
£
Annually (Yearly Salary)
Monthly
Weekly
A – Standard Employee
M – Under 21
H – Apprentice (Under 25)
C – Over State Pension Age
J – Deferment (Employee pays 2%)
Category A is the standard for most employees.
Calculation Results
Gross Annual Income:£0.00
Employee NI (Annual):£0.00
Employee NI (Monthly):£0.00
Employee NI (Weekly):£0.00
Employer NI (Cost to Business):£0.00
Summary: Based on the 2024/25 tax year rates (8% main rate), your total annual National Insurance deduction is estimated at £0.00.
Understanding UK National Insurance Rates 2025
National Insurance (NI) is a fundamental part of the UK tax system, funding state benefits such as the State Pension, statutory sick pay, and maternity allowance. For the 2024/25 tax year (which runs through April 2025), significant changes were made to the rates, specifically reducing the main Class 1 employee contribution rate.
Current Rates for Tax Year 2024/25
As of 6 April 2024, the government reduced the main rate of Employee National Insurance from 10% to 8%. This calculator utilizes these updated figures to provide an accurate estimation of your liability.
Employee (Class 1) Contribution Thresholds
Threshold Name
Annual Amount
Weekly Amount
Rate (Category A)
Primary Threshold (PT)
£12,570
£242
0%
Main Band
£12,570 – £50,270
£242 – £967
8%
Upper Earnings Limit (UEL)
Over £50,270
Over £967
2%
How the Calculation Works
National Insurance is calculated on gross earnings before tax. Unlike Income Tax, which is cumulative over the year, NI is typically calculated on a pay-period basis (though directors have an annual basis).
Standard Rate (8%): You pay 8% on earnings between the Primary Threshold (£12,570) and the Upper Earnings Limit (£50,270).
Higher Rate (2%): You pay 2% on all earnings above the Upper Earnings Limit (£50,270).
Employer Contributions: Employers generally pay 13.8% on earnings above the Secondary Threshold (£9,100 per year).
National Insurance Categories Explained
Your NI category letter determines the rates you and your employer pay:
Category A: Standard category for most employees.
Category M: Employees under 21 (Employer pays 0% up to UEL).
Category H: Apprentices under 25 (Employer pays 0% up to UEL).
Category C: Employees over State Pension age (Employee pays nil, Employer pays standard).
Category J: Employees with deferment (Employee pays 2%, Employer pays standard).
Impact of the 2024 Rate Cut
The reduction to 8% represents a significant saving for the average worker compared to previous years where the rate was as high as 12%. For a salary of £35,000, this reduction saves approximately £900 per year compared to the 12% rate era.
Disclaimer: This calculator provides estimates based on standard Class 1 NI rules for the 2024/25 tax year. It does not account for specific complex scenarios such as directors' cumulative calculations or salary sacrifice schemes. Always consult a qualified accountant or HMRC for definitive figures.
function calculateNI() {
// 1. Get Input Values
var rawIncome = document.getElementById('grossIncome').value;
var period = document.getElementById('payPeriod').value;
var category = document.getElementById('niCategory').value;
// Validation
if (rawIncome === "" || isNaN(rawIncome)) {
alert("Please enter a valid Gross Income amount.");
return;
}
var income = parseFloat(rawIncome);
if (income primaryThreshold) {
// Calculate Main Band (PT to UEL)
var earningsInMainBand = 0;
if (annualIncome > upperEarningsLimit) {
earningsInMainBand = upperEarningsLimit – primaryThreshold;
} else {
earningsInMainBand = annualIncome – primaryThreshold;
}
employeeNI += earningsInMainBand * empRateMain;
// Calculate Upper Band (Above UEL)
if (annualIncome > upperEarningsLimit) {
var earningsAboveUEL = annualIncome – upperEarningsLimit;
employeeNI += earningsAboveUEL * empRateHigh;
}
}
// 6. Calculate Employer NI
var employerNI = 0;
// Logic for Standard Employer NI
if (category === 'M' || category === 'H') {
// Relief applies up to UEL
if (annualIncome > upperEarningsLimit) {
employerNI = (annualIncome – upperEarningsLimit) * employerRate;
} else {
employerNI = 0;
}
} else {
// Standard Calculation
if (annualIncome > secondaryThreshold) {
employerNI = (annualIncome – secondaryThreshold) * employerRate;
}
}
// 7. Format and Display Results
// Helper to format currency
function formatGBP(num) {
return "£" + num.toLocaleString('en-GB', {minimumFractionDigits: 2, maximumFractionDigits: 2});
}
document.getElementById('displayAnnualGross').innerHTML = formatGBP(annualIncome);
document.getElementById('resEmployeeAnnual').innerHTML = formatGBP(employeeNI);
document.getElementById('resEmployeeMonthly').innerHTML = formatGBP(employeeNI / 12);
document.getElementById('resEmployeeWeekly').innerHTML = formatGBP(employeeNI / 52);
document.getElementById('resEmployerAnnual').innerHTML = formatGBP(employerNI);
document.getElementById('summaryTotal').innerHTML = formatGBP(employeeNI);
// Show results area
document.getElementById('results-area').style.display = 'block';
}