Both RD and SIP take a fixed amount every month. An RD is a bank deposit with guaranteed but low, fully taxable returns. A SIP invests in mutual funds — higher long-term growth, market risk, and capital gains tax. The right pick is about timeline, not which product sounds safer.
When RD wins
Goals under 3 years, money you cannot afford to see fall, or building a savings habit before you are ready for equity. Use RD or a liquid fund — not equity SIP — for near-term needs.
When SIP wins
Goals 5+ years away. Historically, equity SIPs have beaten RD rates after tax for long horizons. Volatility is the price of that growth — if you will panic-sell, you are not ready yet.