The 15x15x15 rule is a simple way to plan your mutual fund investments for the long run.  It suggests that if you start an SIP of ₹15,000 at the age of 15, increase it by 15% every year and continue it for 15 years, you can build a sizable corpus by the age of 30. This rule leverages the power of compounding and rupee cost averaging through regular step-up SIPs over a long tenure. By using a step-up SIP calculator, you can see how the 15x15x15 rule works in practice.

Stepup your SIP amount periodically 

A step-up SIP allows you to increase your SIP amount by a fixed percentage each year. For the 15x15x15 rule, you need to increase your SIP amount by 15% each year. For example, if you start a ₹15,000 SIP at age 15, you need to increase it to ₹17,250 at 16, ₹19,837 at 17 and so on each year till 30. Each year, the increased SIP amount is invested in the mutual fund to earn returns.

Power of compounding in action

Through a step-up SIP, the power of compounding works in two ways. Firstly, the returns earned on your investments each year also earn returns in subsequent years, boosting your wealth.  Secondly, the increased SIP amount each year is invested at the higher NAV, earning returns on a larger base. This double benefit of compounding can accelerate your wealth creation.

A step-up SIP calculator demonstrates this. Assuming 12% annual return, ₹15,000 monthly SIP at 15 increasing by 15% yearly can grow to ₹63 lakh by 30. In comparison, a fixed ₹15,000 SIP over 15 years at 12% return will grow only to ₹38 lakh.

Rupee cost averaging

This type of SIP also helps you benefit from rupee cost averaging. Since you invest higher amounts in mutual fund investments when the markets are down and lower amounts when the markets are up each year, your average cost per unit comes down over time. This boosts your returns, especially for equity funds. The step-up SIP calculator shows your average cost per unit decreasing each year, despite market ups and downs.

Change variables to suit your needs

You can modify the 15x15x15 rule to suit your needs using a step-up SIP calculator. For example, you can start at ₹12,000 at 18, increase by 10% each year and continue for 20 years. Or start at ₹25,000 at 22, step up by 20% each year for 10 years. The calculator will show how these modified rules can work for you based on your risk profile and return expectations.


The 15x15x15 rule is a disciplined approach to long-term wealth creation for young investors. Use a step-up calculator to understand how compounding and rupee cost averaging work for regular, increasing investments over the years to achieve your financial goals. Modify the rule to start early, step up higher and stay invested longer for the biggest gains.