As Jaxjacky says it is really complicated. always was, even more so now the new flat rate system has been introduced, for some. Very few people, even now, get the standard amount.
My pension is made up of a proportion of the standard rate, because I do not have a full contribution record to which is added amounts because I made Graduated Pension payments ( a scheme of extra income based units dating back to 1960s-70s), SERPS (State Earnings Related Pension Scheme) because my salary exceeded a certain sum, so that I paid higher contributions and get extra on my state pension.. Some of the SERPS I get 100% of because I was not in any private pension scheme at the time I paid them. If I was in a private pension scheme, providing for the SERPS was devolved to my employer who got some contribution from the government towards them.
If you can make sense of the above, you will understand why everyone has a different pension payment from the government. Then of course in 2016 (or thereabouts) they changed the whole system to a flat rate system, but this has to be phased in over a period of years, so if you are still working, that will also be an element in your pension
As Jaxjacky says. look at a reputable site online like MoneySavingExpert to explain in detail.