Employee NI
Employee National Insurance is deducted through payroll and has its own thresholds and rates. It is separate from Income Tax, so the amount you pay in NI can rise or fall differently even when tax bands stay the same.
Employer NI
Employers also pay National Insurance. Workers do not normally see this on their payslip as part of take-home pay, but it still matters because it affects overall employment cost. Showing employer NI gives users a better way to think about total salary cost and why some employers compare packages carefully.
State Pension age
Employee NI is generally not charged in the same way once someone has reached State Pension age. That is why UK Net Pay includes a simple switch for that situation in its estimate.
Why salary sacrifice changes NI
When pay is reduced before payroll deductions through salary sacrifice, NI can change as well. This is one reason salary sacrifice pension is popular in pay planning conversations.