Calculator Methodology

We document common assumptions so you can interpret results correctly. Exact formulas live in our client-side math library and may be refined over time.

General conventions

• Currency: Indian Rupees (₹), Indian numbering where displayed.
• Compounding: monthly for most SIP/EMI models unless a scheme uses annual compounding (e.g. simplified PPF/SSY models).
• Rounding: display values are typically rounded to nearest rupee.
• Inflation toggles discount future values to today's rupees when enabled.

Examples

• SIP: future value of a monthly annuity with optional annual step-up.
• EMI: reducing-balance loan amortisation; advanced tools support lump-sum prepayments and EMI step-ups.
• XIRR: Newton-Raphson (with bisection fallback) on irregular cash flows.
• Income tax: FY 2025-26 style new-regime slabs and legacy old-regime comparison with Section 87A rebate and 4% cess — update when law changes.

Scheme interest rates (PPF, SSY, NSC, etc.) are configurable inputs with sensible defaults; always confirm the latest notified rate before relying on a maturity figure.