@Miljea there isn’t a simple calculation that will tell you a guaranteed amount, unless you have a “defined benefit” pension, which I think you’d probably know if you did.
More likely you have a “definite contribution” pension - if you’re on auto-enrolment it will be this. It just means that your contribution is defined - that is, you know what you’re paying in, not what you get out.
In that case, what you’re building is a pot of money - your contributions, possibly some from your employer, tax relief on those, and hopefully investment growth.
That gives you two things:
- your actual amount in the pension now: this is a real amount, in your name, but can go up and down if it is invested in shares on your behalf by the pension provider, which is common
- a theoretical projection of how much you will have at age X (maybe 67). That would be assuming you carried on paying in the same, and an assumption of how much it would increase by through investment gains (e.g. shares doing well)
When you access your pension (for a DC type pension you can from 55, though there are some things to be aware of around that, but too detailed for this post) you have choices:
- flexible draw down: you take what you want from the pot, when you want it. Just like drawing money out of your regular bank account today - except that you pay tax on it. It’s treated as income, so same income tax rates apply as if it were your employer paying you a salary. If that seems unfair - that is why the government gave tax relief on your contributions. You don’t pay tax on that part of your salary now, but you do pay tax when you withdraw it much later.
If you have a large pot, you can withdraw what you need - and leave the rest to continue growing (assuming investments do well) No-one can tell you how much it will grow, and it will change year to year. But a common figure used is a 3% withdrawal rate. So if you have £100K, you could take £3K pa, and during that year your £97K would grow - taking you back to £100K.
Another option is called an annuity. These are guaranteed payments, from a company. You take your £100K, and buy an annuity, and the company promises to pay you an amount per year. So - they take the investment risk, and you know what you’ll receive. I can’t say what £100K (as an example) buys, because there are options - and all cost a different amount. For example, some people want their annuity to pay out to their spouse, if they die. In that case, it costs more. You can find annuity calculators online, just like mortgage calculators. Bear in mind that’s today’s purchase price - no-one can predict them if you retire in 40 years time. But it gives you an idea.
Pensions have undergone a lot of change - it’s only this century that “flexible draw down” has been allowed. So no-one can tell you what the future holds (which is why I think OP was unreasonable to be disappointed with her guaranteed pension!) but you can at least get a better idea by looking at the options today.