The FIRE way is 25x the salary you want to have in retirement. If you’re in the US, make an account with the SSA to check your estimated social security benefits. Take the number with a large grain of salt.
Truth be told, it’s all pretty bleak. I save and invest 50% of my income but when I do the numbers for retirement I’ll still be retiring ~65. Personally I’m a skeptic and don’t factor in social security, though. The depressing reality is if you’re saving for retirement then you’re already better off than most.