What Is a Capital Gain?
At its core, the capital gain meaning is straightforward. A capital gain arises when an asset is sold for more than its acquisition cost. The difference between sale value and purchase price is the gain. If the sale value falls short of the cost, the result is a capital loss.
In mutual funds, taxation is triggered only when units are redeemed. NAV fluctuations during holding — however dramatic they may feel in volatile markets — do not create a taxable event on their own. Now, here is where SIP changes the equation slightly.
Each monthly instalment is treated as a fresh purchase. It carries its own NAV, its own timestamp, its own identity, in a sense. When redemption happens, the tax system does not see “one SIP.” It sees multiple purchase lots being sold in a sequence. That sequence is what drives the calculation.
Types of Capital Gains
Capital gains are classified based on how long units were held before redemption. Time — not the size of gain — determines the category.
For equity-oriented mutual funds, the dividing line is 12 months. Units redeemed within 12 months fall under short-term capital gains. For redemptions on or after 23 July 2024, short-term gains on equity-oriented funds are taxed at 20%.
Units held beyond 12 months are treated as long-term. For redemptions on or after 23 July 2024, long-term gains exceeding ₹1.25 lakh in a financial year are taxed at 12.5%, subject to applicable conditions.
Debt-oriented funds operate differently. Units acquired on or after 1 April 2023 are taxed at the investor’s slab rate regardless of how long they are held. For units purchased before that date, earlier long-term provisions may apply depending on the holding period and the rules in force at the time of redemption.
Because SIP instalments are staggered across months or years, a single redemption can gradually quietly contain both short-term and long-term portions. That is worth noting.
Calculating Capital Gain on Mutual Fund SIP
The actual calculation rests on one principle: FIFO — First-In-First-Out. Imagine the SIP as a queue. The earliest units stand at the front. When redemption happens, they exit first.
That ordering matters because the oldest units typically have a longer holding period — and sometimes a very different purchase NAV compared to recent instalments.
The formula itself is not complicated:
Capital Gain = Redemption Value − Cost of Acquisition
Redemption value is simply the number of units redeemed multiplied by the NAV on the redemption date.
Cost of acquisition is calculated using the NAV at which those specific units were originally purchased.
But applying the formula requires careful matching. First, determine how many units are being redeemed. Then identify which instalments those units correspond to under FIFO. After that, calculate the cost for each matched batch.
Next, check how long each batch was held. Finally, classify gains accordingly.
It sounds procedural — and it is — but the logic is intuitive once viewed through time rather than totals. Investors often look at overall portfolio returns and assume tax follows the same summary view. It does not. Tax follows chronology.
Example of Calculating Capital Gain on Mutual Fund SIP
Consider a practical situation. An investor contributes ₹10,000 per month into an equity-oriented mutual fund.
- In January 2023, the NAV is ₹100. That instalment buys 100 units.
- In July 2023, the NAV is ₹111. That instalment buys 90 units.
- In January 2025, the NAV is ₹91. That instalment buys 110 units.
Now the NAV rises to ₹150, and 100 units are redeemed. Under FIFO, the 100 units purchased in January 2023 are treated as sold first.
The calculation becomes direct:
- Redemption value = 100 × ₹150 = ₹15,000
- Purchase cost = 100 × ₹100 = ₹10,000
- Capital gain on mutual fund SIP = ₹5,000
Since these units were held for more than 12 months, the gain qualifies as long-term for equity-oriented funds. For redemptions on or after 23 July 2024, long-term gains exceeding ₹1.25 lakh in a financial year are taxed at 12.5%. If the holding period had been shorter, the gain would have fallen under short-term classification and been taxed at 20%.
The interesting part — perhaps the part investors underestimate — is that the second and third instalments remain untouched in this redemption. Their tax clock continues to run. That is how instalment-based investing intersects with instalment-based taxation.