Are PAYE and National Insurance the same deduction?

No. PAYE is the system for collecting income tax, while National Insurance is a separate deduction with its own rules.

Why can NI drop to a lower rate while tax stays high?

Because employee NI uses its own upper-earnings-limit rule, while income tax keeps following income-tax bands.

Can PAYE and NI look odd in a bonus month even if payroll is right?

Yes. PAYE and NI do not always react to one-off pay in the same way.

Guide

PAYE vs National Insurance Thresholds: Why Tax and NI Start at Different Points

A payslip can look odd simply because tax and National Insurance are not meant to line up exactly.

Reviewed by IsMyPayRight editorial team

Last updated 17 April 2026

Updated for the 2026/27 tax year

Quick answer

PAYE income tax and employee National Insurance are separate deductions with separate rules. In 2026/27 the main annual starting points line up at £12,570 for many employees, but the way each system works after that is still different, so the deduction pattern often diverges.

Why they are separate in the first place

PAYE income tax and National Insurance are different deductions collected through the same payroll. They are not two names for the same thing.

That means they have different starting points, different bands, and different correction rules. A neat-looking salary does not force the tax and NI lines to match each other.

The key 2026/27 numbers

For 2026/27, P9X says the PAYE starting point is £242 a week or £1,048 a month. The employer-thresholds page gives the employee NI primary threshold as £12,570 a year and the upper earnings limit as £50,270 a year.

So the headline annual starting point often looks similar, but the system above that point is not the same.

How the rates differ after the threshold

Income tax steps through the income tax bands for your region. Employee NI uses an 8% main rate up to the upper earnings limit and 2% above that in 2026/27 for category A employees.

That is why NI can flatten out at higher salaries even while income tax keeps rising.

Why pay frequency can make the lines look odd

PAYE is usually cumulative across the year when the code is normal. National Insurance is usually worked out per pay period. So a bonus month can distort the relationship between the two lines even when payroll is doing exactly the right thing.

This is one of the most common reasons people think a payslip is wrong when it is really just two different systems behaving as designed.

Break the payslip into separate systems

If one line looks odd, test tax and NI separately instead of assuming one should explain the other.

When a mismatch really is a warning sign

You should worry more when the mismatch comes with another obvious clue, such as BR, D0, M1, W1, or a deduction line that changed the taxable gross pay unexpectedly. Without those clues, a simple PAYE-versus-NI difference is often normal.

The right approach is to test each line against its own rules rather than expecting them to mirror one another.

What to check

PAYE is about income tax, not NI.
NI is calculated under different thresholds and bands.
A payslip can have tax but little NI, or NI but little tax, depending on the situation.

What to do next

Look at the tax and NI lines separately instead of assuming one explains the other.
Use the calculator if you want to see where the NI rate drops at higher pay.
Use the checker if one line looks odd but the other looks normal.

Try the tool

Use the checker if you already have a payslip. Use the calculator if you want to model take-home pay or salary-sacrifice changes before payday.

Why you can trust this guide

This guide is maintained by the IsMyPayRight editorial team team and is aligned to the PAYE assumptions used by the calculator and payslip checker.

We write against HMRC rules first, then explain the payroll implications in plain English so the article and the tool stay consistent.

Methodology and sources

UK PAYE guidance content is backed by the same methodology used across the engine and checker.

Common questions

Are PAYE and National Insurance the same deduction?: No. PAYE is the system for collecting income tax, while National Insurance is a separate deduction with its own rules.
Why can NI drop to a lower rate while tax stays high?: Because employee NI uses its own upper-earnings-limit rule, while income tax keeps following income-tax bands.
Can PAYE and NI look odd in a bonus month even if payroll is right?: Yes. PAYE and NI do not always react to one-off pay in the same way.

Official sources

We checked the claims in this guide against the official source pages below and the current 2026/27 calculator rules.