People say "I have a SIP" as if it were a product. It is not. A SIP is a way of paying into a mutual fund: the same amount, on the same date, every month. That small difference changes how you should think about it, and it explains why the plain habit often does better than clever timing.
A SIP is an instruction, not a scheme
SIP stands for Systematic Investment Plan. You pick a mutual fund, an amount and a date. On that date each month, the amount is debited from your bank account through a mandate and invested in the fund at that day's NAV, the price of one unit. Nothing more happens behind the scenes.
So when someone asks "which SIP is good?", the real question is which fund category suits the goal. The SIP itself has no return of its own. It carries whatever the underlying fund does, good months and bad.
- You can start with as little as ₹500 a month in most categories.
- You can pause, change the amount or stop at any time. There is no penalty for stopping the instruction.
- Units you already bought stay invested until you redeem them. Stopping a SIP does not sell anything.
- Exit loads and tax apply when you sell units, the same as for a one-time investment.
How units are bought each month
A mutual fund unit has a price, the NAV, that changes every working day. Your fixed amount buys more units when the NAV is low and fewer when it is high. That is the whole idea of rupee cost averaging: you never decide when to buy, so you cannot get the timing badly wrong, and the falls in between quietly lower your average cost.
A worked example: six months, ₹5,000 each month
Say the NAV of a fund moves like this over six months. The numbers are made up to show the mechanics, not taken from any real scheme.
| Month | NAV (₹) | Amount invested | Units bought |
|---|---|---|---|
| 1 | 50 | ₹5,000 | 100.0 |
| 2 | 45 | ₹5,000 | 111.1 |
| 3 | 40 | ₹5,000 | 125.0 |
| 4 | 42 | ₹5,000 | 119.0 |
| 5 | 48 | ₹5,000 | 104.2 |
| 6 | 55 | ₹5,000 | 90.9 |
| Total | ₹30,000 | 650.2 |
Three things to notice:
- Your average cost is ₹46.14 a unit (₹30,000 divided by 650.2 units). The simple average of the six NAVs is ₹46.67. Because you bought more units in the cheap months, you paid less than the plain average.
- Months 2 to 4 felt bad but did the most work. The NAV was below where you started, yet those three instalments bought 355 units, more than half the total.
- At a NAV of ₹55, your 650.2 units are worth about ₹35,760. Had you put all ₹30,000 in at ₹50 in month 1, you would hold 600 units worth ₹33,000.
The last point is not a rule. If the market had only gone up from month 1, the one-time investment would have come out ahead, since all the money was in from the start. Rupee cost averaging does not beat the market. It removes the need to guess the right day, and it makes falls useful instead of frightening. Our article on SIP or lumpsum covers when a single investment makes more sense.
What a SIP does over longer periods
Six months shows the mechanics. Ten or fifteen years shows the point. As an illustration, ₹5,000 a month for 10 years is ₹6,00,000 invested. At an assumed rate of 12% a year for illustration, it would grow to roughly ₹11.6 lakh. Actual returns can be higher, lower or negative, and equity funds can stay below cost for a year or more along the way.
12% a year is an assumed rate for illustration, not a promise or a forecast. Mutual fund investments are subject to market risks, read all scheme related documents carefully.
The bigger lever is time, not the fund. The same ₹5,000 started five years later has half the years to compound. Try your own numbers in the SIP calculator, or see what waiting costs with the cost of delay calculator.
Where a SIP fits, and where it does not
A SIP into an equity or hybrid category suits goals five years or more away: retirement, a child's education, a home down payment. For money you need within a year or two, the monthly habit is still useful, but into a debt or liquid category, where the swings are smaller. Your emergency fund should not sit in an equity SIP at all.
A few habits that matter more than the fund you pick:
- Pick a date just after salary day, so the debit never bounces.
- Raise it once a year. A step-up of 10% each April, in line with your pay rise, adds far more over 15 years than switching funds.
- Do not stop when the market falls. That is exactly when the instalments buy the most units, as months 2 to 4 above show.
- Review once a year, not once a week. Check the category still fits the goal and the amount still fits your income.
Common questions
Is my money locked in a SIP?
No, except in an ELSS fund, where each instalment has its own 3-year lock-in. In other categories you can redeem units any time, though an exit load may apply if you sell within a set period, often one year in equity funds.
What if I miss a month?
That instalment is simply skipped. Your bank may charge a fee for the failed debit. After several missed instalments in a row, the fund house may cancel the instruction, but the units you already bought stay with you.
Monthly or weekly SIP?
Over many years the difference is small. Monthly is easier to track and lines up with salary. Pick the one you will keep running.
How is a SIP taxed?
Each instalment is treated as a separate purchase, so the holding period is counted from its own date. Equity fund gains held over 12 months are long-term, with gains up to ₹1.25 lakh a year exempt and the rest taxed at 12.5%. Rules as of 2026, check current rules before you sell.
General information, not investment advice or a recommendation of any scheme. Any return figure here is an assumed rate for illustration. Mutual fund investments are subject to market risks, read all scheme related documents carefully. Past performance may or may not be sustained in future.
