Use the official GOV.UK State Pension forecast service and check your estimated amount, State Pension age and the number of qualifying National Insurance years recorded. Compare this with your National Insurance record, looking for missing years, gaps, credits or periods when you were contracted out. The forecast may show whether paying voluntary contributions could increase your entitlement, but check the cost and likely benefit before paying, as it will depend on your individual record. If anything looks wrong, contact HMRC or the Future Pension Centre for guidance.