Employer social-insurance costs in the United Kingdom
Reviewed by Mellow Editorial Team, HR & payroll content team
Employer social-insurance costs in the UK come down primarily to one charge: Class 1 secondary National Insurance contributions (NICs), paid on top of each employee's gross wages. At 13.8% on earnings above the secondary threshold, it is often the largest employment cost beyond the salary itself.
What counts as employer National Insurance
Employer NICs are Class 1 secondary contributions. You pay them on behalf of the business — they are separate from, and in addition to, the employee's own NICs, which are deducted from the employee's wages.
The rate is 13.8% on earnings above the secondary threshold (category A employees). Below that threshold, you pay nothing. Above it, every pound of gross pay attracts the 13.8% charge with no upper limit — unlike employee NICs, which drop to 2% above the upper earnings limit.
This means the cost compounds quickly as salaries rise. A £50,000 salary generates a meaningfully larger employer NIC bill, proportionally, than a £25,000 salary once you account for the threshold.
How employer NICs are calculated and paid
The calculation runs through your payroll software each pay period:
1. Take the employee's gross pay for the period.
2. Subtract the secondary threshold for that period (the annual figure pro-rated to weekly or monthly).
3. Multiply the remainder by 13.8%.
4. Add the result to your PAYE liability for that period.
Payment goes to HMRC alongside income tax and employee NICs, usually by the 19th of the following month (22nd if paying electronically). Under Real Time Information (RTI) rules, you must also submit a Full Payment Submission (FPS) on or before each payday — the liability and the report travel in parallel, but they are separate actions.
If you miss the FPS deadline, HMRC can issue penalties, so most employers rely on payroll software that submits automatically.
Auto-enrolment pension contributions add to the total
Employer NICs are not the only statutory cost on top of salary. Auto-enrolment pension contributions are also mandatory for eligible workers. The employer minimum is 3% of qualifying earnings; employees contribute a minimum of 5%.
Qualifying earnings are not the same as total gross pay — they are calculated on a band of earnings, so the actual pension cost per employee depends on where their salary sits within that band.
When you are modelling the true cost of hiring, add the employer pension contribution to the NIC figure. For a mid-range salary, the combined uplift on top of gross pay is substantial.
The Employment Allowance
Many smaller employers can reduce their NIC bill through the Employment Allowance, which offsets employer NICs up to a set amount each tax year. Eligibility conditions apply — notably, companies where the sole employee is also a director are excluded. If you qualify, the allowance is claimed through your payroll software when submitting RTI returns, and HMRC applies it against your running liability automatically.
This can make a genuine difference to cash flow for small businesses, bringing the effective NIC cost per employee down considerably in the first part of the tax year.
Other employer obligations that carry a cost
Beyond NICs and pensions, a few other statutory obligations have financial implications worth tracking:
Statutory Sick Pay (SSP) — employers must pay SSP to eligible employees who are off sick. You cannot currently reclaim SSP from HMRC in most cases, so it represents a direct cost.
Statutory family leave pay — statutory maternity, paternity, adoption and shared parental pay are funded by the employer and then reclaimed from HMRC (smaller employers may be able to reclaim more than they pay out, depending on their NIC bill). The administration still falls to you.
Annual leave — employees are entitled to 5.6 weeks' statutory paid leave (28 days including bank holidays for a standard five-day week). This is a cost built into salary rather than an add-on charge, but it is worth factoring into headcount planning.
The Employment Rights Act 2025 has also strengthened day-one rights for employees, which affects how quickly certain entitlements apply from the start of employment. Staying current with these changes matters both for compliance and for budgeting accurately.
Putting the total cost of employment together
A practical rule of thumb: take gross salary, add roughly 13.8% for employer NICs on the portion above the secondary threshold, add 3% for pension contributions on qualifying earnings, and account for the cost of statutory leave. The result is consistently higher than the headline salary figure — sometimes 20% or more above it for full-time employees earning above the threshold.
Running this calculation before agreeing a salary, rather than after, avoids the common problem of payroll costs arriving as a surprise at the end of the first pay period.
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