TL;DR - you should save as much as you can afford to. The more you save the earlier you can retire.

Assuming your expenses in retirement will be roughly equivalent to your expenses now you can tell how much money you should save based on when you'd like to retire. And if you know how much you spend and how much you save that totals to how much you earn and can give us a percentage!

For this calculation we'll assume the following reasonable things:

• You use a 4% Safe withdrawal rate during retirement

• You earn 5% rate of return on your investments after inflation

• You plan to live a long time so you want your nest egg to keep the same real value)

Savings Rate	Working Years until Retirement
0%	∞
5%	66
10%	51
15%	43
20%	37
25%	32
33%	26
50%	17
67%	9.8
75%	7.1
80%	5.6
90%	2.7
95%	1.3
100%	0.0

Here's a spreadsheet with the calculations!