Income tax gets all the attention, but there is a second deduction quietly leaving your pay each month: National Insurance. Most people pay it for decades without quite knowing what it is or what it buys.
What it pays for
National Insurance funds the State Pension and contributes towards certain benefits, such as some unemployment and maternity support. Crucially, your record of contributions is what builds your entitlement to the State Pension later, so it is not just a tax — it is a ledger of what you are owed.
The main classes
- Class 1 — paid by employees, taken automatically from wages above a threshold.
- Class 2 and Class 4 — paid by the self-employed, sorted through Self Assessment.
- Class 3 — voluntary contributions to fill gaps in your record.
Thresholds matter
You only start paying once your earnings pass a set level, and there are points where the rate steps down on higher earnings. The exact figures shift from year to year, so it is worth glancing at the current thresholds rather than assuming.
The bit worth remembering
Because contributions build State Pension entitlement, gaps can cost you in retirement. Time spent not working — raising children, caring, or studying — can sometimes be covered by credits, but only if you claim them. If you take a career break, check whether you qualify for credits so your record keeps ticking over. A quiet deduction now is really a deposit towards later.