Question: how do you know if your paying too much national insurance?
Answer: There is no upper limit on employer's National Insurance (NI) payments. ... you pay National Insurance contributions if you earn more than £183 a week for 2020-21. you pay 12% of your earnings above this limit and up to £962 a week for 2020-21. the rate drops to 2% of your earnings over £962 a week.