About e309 Calculator

What this is

e309 Calculator is a free set of financial calculators for India — SIP, EMI, income tax, retirement planning, Post Office savings schemes, and more, currently 39 in total. There's no sign-up, no account, and no paywall on any calculator.

How the calculations are built

Every formula is written from the underlying financial math or the scheme's own published rules — Post Office scheme rates, for instance, are updated from the rates the government actually publishes each quarter, not estimated. Where a calculator simplifies something real (an EMI calculator ignoring processing fees, a retirement calculator assuming a constant rate of return), that simplification is stated directly on the calculator's own page, not left implicit.

Each calculator states a "last reviewed" date, and its explainer section describes exactly what it does and doesn't account for. These are estimates for planning purposes — see the privacy policy for how information is handled, and treat any figure here as a starting point to verify independently, not as financial advice.

How this site is funded

Through advertising, where enabled — the same conditional basis described in the privacy policy. Calculations themselves are never influenced by this: the formulas and figures shown are identical regardless of what's advertised on any given page.

Feedback and corrections

Every calculator has a "Something look wrong?" link for reporting a specific issue with a specific calculation — this is the fastest way to get an error looked at, since it captures the exact inputs involved. For anything else, write to calculator@e309.in.