There's no single magic number, but there are useful frameworks. The key insight: your savings rate matters more than perfect precision, especially early. Educational only.
A common rule of thumb is to save around 15% of income for retirement (including any employer match). If that's not possible now, start lower and raise it over time — the habit and consistency matter most.
Early on, your contributions drive your balance far more than investment returns do. Later, compounding takes over. So the most powerful early move is simply saving a meaningful, consistent percentage.
If you have an employer 401(k) match, getting the full match is the highest-priority "savings" — it's an instant return.
Bump your savings rate a little each time your income rises, before lifestyle creep absorbs it. Automating this makes it painless.
As retirement nears, you can estimate a target based on your expected expenses. Early on, don't let a scary big number stop you — start saving a solid percentage now and refine as you go. Consult a professional for personalized planning.