Budgeting
Savings rate
Savings rate is the percentage of your take-home income that you don't spend and instead put toward saving, investing or paying down debt.
Formula: Savings rate = (income − expenses) / income
It's the variable that most shortens the path to financial independence, because it both increases what you accumulate and reduces the capital you'll need to live on.
A 20% rate is a reasonable target; above 40% the timeline shortens dramatically.