How much National Insurance do I pay? The amount of National Insurance (NI) you pay depends on your age and how much you earn. For most people under State Pension age, it’s calculated at 12% of earnings above £183 per week (or £732 per month), and 2% of any earnings over £962 per week. If you aren’t paid one week and are on a cumulative tax code, your £183 weekly NI-free allowance will carry over, resulting in lower contributions the next week. These figures are correct for the 2020/21 tax year.