Money rules of thumb
Shortcuts that are close enough to be useful and simple enough to remember. Each one comes with the fine print about where it stops working.
Rule of 72
Divide 72 by your annual return to estimate the years it takes to double your money.
Rule of 114
Divide 114 by your annual return to estimate the years it takes to triple your money.
Rule of 144
Divide 144 by your annual return to estimate the years it takes to quadruple your money.
Rule of 70
Divide 70 by the inflation rate to see how long until your money buys half as much.
Rule of 25
Multiply your annual expenses by 25 to estimate the corpus you need to stop working.
50-30-20 Rule
Split take-home pay 50% needs, 30% wants, 20% savings.
100 minus age
Hold roughly (100 − your age)% in equity, the rest in debt.
3-6 month rule
Keep three to six months of expenses in accessible cash.
10-15× income rule
Carry life cover worth 10 to 15 times your annual income.