In financial planning application, most have heard about Rule 72. **It’s an useful estimate to double your money at a given time.**

To estimate the time it will take to double your money, divide 72 by the expected growth rate, expressed as a percentage.

For example, if you expect to earn 10% per year on a $10,000 investment, it will double to $20,000 in about 7.2 years (72 / 10).

How about triple your money?

**Apply Rule 114**. It can be used to determine how long it will take an investment to triple.

For example, at 10% an investment will triple in about 11 years (114 / 10).

Naturally, you will think of quadruple your money!

Use Rule 144, you can guess that it’s a “double-double” effect of Rule 72.

So at 10%, an investment will quadruple in about 14.5 years (144 /10).

How about Rule “73.5”?

**There is no such rule.**

Personally, I have improvised to have a quick estimate on the annual investment where the numbers of times the interest rate equals 72, the ending value will equal approximately 1.5 times the amount invested.

**So Rule “73.5” is based on 72 + 1.5.**

For example, investing $10,000 per year for 8 years at 9% interest (8 * 9 = 72), the value of the investments at the end of year 8 will equal about $120,000 ($10,000 * 8 * 1.5).

To check the “accuracy” of this Rule “73.5”, punch a few buttons on the financial calculator, you will get the values FVAD (pmt=-$10,000, n=8, i%=9, BGN) = $120,210!

**Bingo!** A great estimate, isn’t it?

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*Chew* **Hock Beng***is a Certified Financial Planner, Chartered Financial Consultant, Chartered Life Underwriter & Chartered Family Office Specialist. He has community involvement experience and has held appointments like Honorary Treasurer & Exam Board Chair with Financial Planning Association of Singapore (FPAS), Education Sub-committee with IFPAS, PSG Chairman. Hock Beng is a certified IBF instructor with Financial Perspectives and an Adjunct Trainer with Falco Academy. Currently he is managing a team of independent financial adviser representatives, providing* *training**,* *mentoring* *& coaching.*