Answers · UK 2025/26

Do I pay National Insurance on a second job?

Yes. National Insurance is calculated separately for each employer, so you get the £12,570 Primary Threshold applied afresh in each job, potentially meaning you pay less total National Insurance than if the same combined income came from a single employer, though this can also mean you underpay in some cases.

Last updated: 3 July 2026Last reviewed: 3 July 2026How we verify

Full answer

National Insurance for employees is calculated on a per-employment basis, not on your combined total income across all jobs, which is different from how Income Tax works (where HMRC tries to allocate your Personal Allowance across jobs via your tax code, and taxes total income progressively). Each employer applies the £12,570 Primary Threshold independently when calculating National Insurance, meaning if you have two jobs each paying £15,000, National Insurance in each job is calculated as if that were your only income -- 8% on the amount above £12,570 in each job separately, rather than 8% on the combined £30,000 as a single calculation would produce. In some cases, this can mean you pay less total National Insurance across two modest part-time jobs than someone earning the identical combined amount from a single employer, since you effectively benefit from the Primary Threshold twice. However, if your combined earnings across all jobs would push you into the higher 2% National Insurance band that applies above the £50,270 Upper Earnings Limit, having several employers means none of them individually applies that higher earnings limit calculation correctly for your combined position, and you can end up needing to claim a National Insurance refund or, in some circumstances, apply for deferment in advance if you know you will be significantly overpaying across multiple jobs at a high combined income. HMRC's National Insurance rules allow you to apply to defer Class 1 National Insurance in one job if you already expect to reach the Upper Earnings Limit through another.