Methodology & assumptions
This page documents exactly how the calculators on My SIP Planner behave in code: compounding frequency, order of cash flows, and what we deliberately leave out. It exists so readers can separate teaching aids from real-world fund statements or loan agreements.
Last reviewed for accuracy against the site's calculator module: April 2026.
Why we publish this
Ad networks and search quality guidelines both reward sites where the utility is obvious: what you built, how it works, and where the limits are. The following matches the implementation in our calculators todaynot a generic finance textbook.
SIP (monthly instalments)
We treat your inputs as a fixed monthly amount, a flat annual return you type in, and a whole number of years. The engine converts the annual percentage to a monthly rate with annual ÷ 12 ÷ 100, then values the stream with monthly compounding using the closed form for a series of equal payments, including the (1 + monthlyRate) factor you see on the SIP calculator page. That factor matches the annuity-style timing baked into our formulanot NAV-by-NAV history from any AMC.
The year-by-year table snapshots the running total of contributions and the theoretical corpus at each anniversary. It smooths returns; it does not model market crashes, fund manager changes, expense ratio drags, or pausing an SIP when cash flow is tight.
Lumpsum and “mutual fund returns” (one-time purchase)
One-time investments use compound growth on the principal only: future value equals principal multiplied by (1 + r)^n where r is the annual rate as a decimal and n is years. Charts mark the same principal each year while the curve shows hypothetical value. Again, no daily NAV path, dividends, or tax accruals.
SWP (systematic withdrawal)
The SWP simulation walks month by month for up to the tenure you enter. Each month we withdraw the requested amount (or whatever balance is left if it is smaller), then apply the same monthly rate to the remainder. If the balance hits zero before the horizon ends, the tool flags an early depletion. That orderwithdraw first, then growmirrors the comment in our source and is useful for “can this withdrawal last?” conversations, but it is still a toy model: real SWPs follow AMC cut-off times, minimum balances, stamp duty or STT on redemptions, and volatile NAVs.
EMI (reducing balance loan)
We use the textbook equated monthly instalment on monthly rests: principal outstanding accrues interest at annual ÷ 12, each payment pays interest first then principal, and the chart tracks outstanding balance versus cumulative interest. Processing fees, insurance bundles, floating rate resets, moratoriums, and prepayment penalties are not modeled.
What we never claim
- Past or future performance. Any percentage you type is an assumption for learning, not a forecast from My SIP Planner.
- Tax, regulatory, or suitability advice. ELSS lock-ins, capital gains treatment, surcharge slabs, and whether a product fits you require a qualified professional and official documents.
- Live data. We do not scrape AMC sites for NAVs or connect to broking APIs. The value is in transparent math and charts you control.
Editorial & corrections
If you spot a mismatch between this page and the live tool, tell uswe treat that as a bug report, not a debate.
See also our editorial standards for how articles are written and reviewed, and the disclaimer for the legal framing. Nothing here is a substitute for scheme documents, loan sanction letters, or advice from a SEBI-registered investment adviser.