What is the (100 − age) rule?
One of the most important decisions in investing isn't what to buy, but how to split your money between growth assets and stable assets. The (100 − age) rule is a time-tested rule of thumb that says the percentage of your portfolio held in equity should be 100 minus your age, with the remainder in debt.
A 30-year-old would hold roughly 70% equity and 30% debt, while a 60-year-old would hold 40% equity and 60% debt. The logic is straightforward: the younger you are, the more time you have to recover from market downturns, so you can afford to take on more equity risk. As you grow older, the mix gradually shifts towards safer debt instruments to protect what you've already built.
How does the Asset Allocation Calculator work?
The calculator applies the rule directly to your age using one formula:
Equity % = 100 − Your Age | Debt % = Your Age
Worked example: Enter an age of 30, and the calculator returns an allocation of 70% in equity and 30% in debt. At age 36, the same formula gives 64% in equity and 36% in debt. Move the age slider and the donut chart updates instantly to show your new recommended split.
Equity vs debt — what's the difference?
Equity refers to stocks and equity mutual funds. They offer higher long-term growth potential, but come with more short-term volatility.
Debt refers to bonds, fixed deposits and debt funds. They offer lower but steadier, more predictable returns that help protect your capital.
The (100 − age) rule balances these two by giving younger investors more exposure to equity's growth potential, while shifting older investors towards debt's stability as their investment horizon shortens.
How do I use Chola Securities' Asset Allocation Calculator?
Simply set your age using the slider or input box. The calculator instantly shows the recommended share of your portfolio to hold in equity and in debt, displayed as an easy-to-read donut chart. Use it as a starting point and adjust the mix to suit your goals and risk appetite.
Advantages of using the Asset Allocation Calculator
- Get an instant, age-appropriate equity-to-debt split — no manual maths needed.
- Visualise your ideal portfolio mix with a clear donut chart.
- Understand how your allocation should evolve as you age.
Remember that this is a general guideline. Your ideal allocation also depends on your income, financial goals, and personal comfort with risk.