The rule of 72, and when money doubles.
The rule of 72 says money doubles in about 72 divided by the rate years. How close it is, with the exact figure beside it.
By Suraj Kumar3 min read
A quick rule tells you roughly when money doubles. Here is how close it is.
The rule.
Divide 72 by the yearly rate: at 6% that is 12 years.
Exactly.
The exact time is ln 2 divided by ln(1 + r): 11.9 years at 6%. The rule is close at ordinary rates and drifts at high ones; the page shows both.
A lump sum.
One amount left to grow at a steady rate; the answer says what it comes to and when it doubles.
Further reading
Topics: rule of 72 · lump sum calculator · doubling time · money doubling · lumpsum investment
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