Employer National Insurance Calculator (UK)
Estimate employer Class 1 Secondary National Insurance contributions for a single employee based on annual salary.
This is a simplified estimator and does not include NI category letters, apprentices under 25, under-21 rates, or director annual earnings period calculations.
What this employers national insurance calculator does
This page helps you estimate how much National Insurance an employer pays for one employee in the UK. If you run payroll, budgeting for employer NI is essential because it increases your true employment cost above gross salary.
The calculator focuses on Class 1 Secondary (Employer) National Insurance. You enter a gross annual salary, choose a tax year, and optionally apply Employment Allowance to estimate the amount still payable.
How employer National Insurance works
In simple terms, employer NI is charged at a percentage rate on earnings above a yearly threshold. Two key moving parts determine the final number:
- Secondary Threshold: earnings below this amount are not charged at the main employer NI rate.
- Employer NI rate: the percentage applied to earnings above the threshold.
For many employers, Employment Allowance can then reduce the final NI bill, sometimes to zero.
Rates and thresholds used in this tool
Tax year 2024/25
- Secondary Threshold: £9,100
- Employer NI rate: 13.8%
- Employment Allowance: up to £5,000
Tax year 2025/26
- Secondary Threshold: £5,000
- Employer NI rate: 15%
- Employment Allowance: up to £10,500
Calculation formula
The core calculation is straightforward:
- Taxable earnings for employer NI = max(0, salary − threshold)
- Gross employer NI = taxable earnings × rate
- Allowance remaining = max(0, annual allowance − already used)
- Employer NI due = max(0, gross employer NI − allowance remaining)
The calculator also shows monthly and weekly equivalents so payroll planning is easier.
Example: quick scenario
Suppose one employee earns £35,000 in tax year 2025/26:
- Taxable earnings: £35,000 − £5,000 = £30,000
- Gross employer NI: £30,000 × 15% = £4,500
- If you still have enough Employment Allowance left, that £4,500 may be fully offset.
If your allowance is already used up, then the full £4,500 is payable.
Why businesses use an employers national insurance calculator
- Hiring decisions: compare total employment cost, not just salary.
- Forecasting: project payroll taxes over the year.
- Cash flow control: avoid surprise liabilities each month.
- Scenario planning: test salary increases before committing.
Important limitations to know
This tool gives a practical estimate, but real payroll can be more complex. Results can differ where special NI rules apply, including:
- NI category letters and reduced/zero rates in specific circumstances
- Employees under 21, apprentices under 25, and veterans relief rules
- Directors (annual earnings period methods)
- Irregular pay periods and payroll timing effects
- Eligibility constraints for Employment Allowance
For filings and legal compliance, always confirm with HMRC guidance or your payroll professional.
Frequently asked questions
Is this calculator for employee NI or employer NI?
Employer NI only. Employee deductions are separate and calculated differently.
Can I use this for multiple employees?
Yes, calculate each salary one by one, then total the results. For full payroll-level accuracy, use dedicated payroll software.
Does Employment Allowance apply automatically?
No. You must be eligible and claim it. This calculator lets you switch it on/off and account for allowance already used.
Is this suitable for statutory reporting?
No. It is a planning estimator. Use your payroll system and HMRC-compliant rules for official submissions.
Bottom line
An employers national insurance calculator is one of the fastest ways to understand the real cost of employing staff. Use it whenever you price roles, plan growth, or review payroll strategy. Even small salary changes can meaningfully affect employer NI over a full year.