The amount of your state pension is largely determined by how many years of NIC you have completed during your working life. You can check your NIC record in your online personal tax account.
You normally need 35 full years of NIC to receive the maximum state pension and ten complete years to receive any state pension. If you are under 45 you have plenty of time before you reach the state retirement age of 67 (or possibly 68) to make up for any gap years in your NIC record.
If you are 45 or older you have less time to pay NIC in the regular way on your wages or as a self-employed trader. The Government is currently encouraging women born after 5 April 1953 and men born after 5 April 1951 to make up any deficiency in their NIC record.
If you fall into this group you can pay voluntary NIC at £15.85 for each missing week in any tax year back to 2006-07 but this payment must be made by 31 July 2023. Payments after that date can only be used to fill NIC gaps in the years 2017-18 to 2022-23 and must be paid at the higher rate of £17.45 per week.
Paying voluntary NIC is effectively an investment decision. Consider whether paying extra NIC now will pay back sufficiently in the form of extra state pension over your expected lifetime.