It seems obvious that investing twice as much money should get you roughly twice the result. Over a 25-year horizon, that intuition turns out to be wrong — doubling your monthly SIP amount does more than double your final outcome, because compounding doesn't scale in a straight line.
The actual 25-year numbers
| SIP Amount | Total Invested (25 yrs) | Value at 12% CAGR | Returns Earned |
|---|---|---|---|
| ₹5,000/month | ₹15 Lakhs | ₹94.9 Lakhs | ₹79.9 Lakhs |
| ₹10,000/month | ₹30 Lakhs | ₹1.89 Crore | ₹1.59 Crore |
Why this isn't a simple 2x relationship
The ₹10,000/month investor put in ₹15 lakhs more of their own money than the ₹5,000/month investor — but ended up with nearly ₹95 lakhs more overall. That extra gap, beyond the simple doubling of contributions, is pure compounding at work: a bigger monthly base generates proportionally bigger absolute growth each year, which itself becomes the base for the following year's growth. This is the same mechanism explained in the power of compounding.
Can't afford ₹10,000/month right now? Start with ₹5,000 today
Here's the more important, more actionable lesson: a 1-year delay in starting costs you some of the most valuable compounding years of your investing life, regardless of which amount you eventually reach. Rather than waiting until you can afford ₹10,000/month, start at ₹5,000 today and increase it by roughly 10% every year as your income grows — a Step-Up SIP.
A worked example
Someone starting at ₹5,000/month with a 10% annual step-up will, within a handful of years, be contributing amounts close to or beyond ₹10,000/month — while having already benefited from several extra years of compounding on the earlier, smaller contributions. That combination frequently outperforms someone who waited a few years to start at the full ₹10,000/month, purely because of the head start.
Common mistakes to avoid
- Waiting to start until you can afford the "ideal" SIP amount — starting smaller today beats starting bigger later.
- Assuming the relationship between SIP amount and final corpus is linear — it isn't, which is exactly why starting early matters so much.
- Keeping the SIP flat for 25 years instead of stepping it up as income grows.
Key takeaways
- Doubling your SIP amount more than doubles your final corpus over a long horizon — compounding isn't linear.
- Starting smaller today beats waiting to start bigger later.
- A Step-Up SIP lets you begin at ₹5,000 and grow toward ₹10,000+ without a painful jump.
- Use the SIP Calculator and Step-Up SIP Calculator to project your own numbers.
FAQs
How much should I actually be investing each month?
It depends on your salary and expenses — see the full breakdown in how much to invest based on your salary.
What if I'm just starting out and have never invested before?
Start with the basics in what is a SIP — it walks through opening an account and making your first investment.
Is 12% CAGR realistic for a 25-year SIP?
It's a reasonable long-term historical average for Nifty 50 index funds, but not a guarantee — actual returns will vary considerably year to year.