Compare what the same annual contribution could grow to via a SIP versus PPF.
SIP maturity: Standard SIP future-value formula
PPF maturity: Standard PPF annual compounding formula
Why is PPF capped at 15 years in this comparison?
PPF has a fixed 15-year tenure by design (extendable afterward in blocks), so if you choose a longer comparison period, the PPF side of the calculation still reflects only what its standard term would actually produce.