National insurance number
Your National Insurance number is on payslips, P60s, or letters about tax, pensions and benefits. You can also find it through your online personal tax account and download a confirmation letter.
If cannot find it, or cannot log into your personal tax account, call the National Insurance helpline on 0300 200 3500 or visit their website. They won’t tell you your National Insurance number over the phone. They’ll post it to you and it’ll arrive within 10 working days.