How We Calculate
Every rupee figure on this site comes from one of two places: a stated assumption put through a formula, or a published number with a date and a source. This page lists both, so any figure can be checked.
The default assumptions
Unless a page says otherwise, calculations use:
| Assumption | Value | Why this number |
|---|---|---|
| Equity return, before costs | 12% a year | Roughly what diversified Indian equity has returned over long periods. Not a forecast: individual ten-year periods have been well above and well below it. |
| Inflation | 6% a year | Close to India's long-run consumer inflation. Education and healthcare are assumed at 8–10% where a page says so. |
| Compounding | Monthly | Returns are applied each month at the annual rate ÷ 12. |
| SIP timing | Start of each month | Each instalment earns that month's return. |
| Tax | FY 2026-27 rates plus 4% cess | Surcharge is ignored unless stated, because it applies only to incomes above ₹50 lakh. |
| Fund costs | Deducted from the return | A 0.5% expense ratio on a 12% return is modelled as 11.5%. |
Where a page uses different figures, it states them next to the calculation.
The formulas
A monthly SIP of P for n months, with a monthly rate r (annual rate ÷ 12):
A lump sum L for t years at annual rate R:
Today's cost C of a goal, grown at inflation i for t years:
Step-up SIPs apply the SIP formula year by year, raising the monthly amount at the start of each year. Tax-harvesting figures simulate every year of a SIP and treat harvested gains as long-term. The pages that use this say it is an approximation.
The site's SIP calculator and compound interest calculator use the same formulas, so you can reproduce any figure with your own inputs.
Where company and market data comes from
| Data | Source | Notes |
|---|---|---|
| Company financials | Screener.in, from companies' annual reports | Consolidated figures. Screener groups balance-sheet lines into broad heads, so the annual report shows more detail under the same totals. |
| Share prices, PE, ROE | Screener.in | Taken on the date shown on the page. Prices change every trading day. |
| Index valuation (Nifty 50 PE) | NSE, via index valuation trackers | Several trackers publish slightly different readings for the same week. The page gives the range. |
| Tax rules | Income-tax Act and Union Budget announcements | Checked after each Budget. |
| Mutual fund rules | SEBI regulations and circulars | Including the expense-ratio framework in force from 1 April 2026. |
What "figures checked" means
Every guide shows the date its figures were last checked against their sources. A page is checked again:
- after every Union Budget, for pages with tax rates;
- after companies publish annual results, for pages using company financials;
- at least once a year for everything else.
A script in the site's code lists every page whose check date has run past its refresh period, so a stale page gets noticed instead of left to drift.
What a figure is, and what it is not
- An illustration of arithmetic. "₹10,000 a month for 20 years at 12% becomes ₹1 crore" is exact arithmetic on stated inputs. Real returns will differ, possibly by a lot.
- A dated fact. "TCS closed at ₹2,082 on 25 September 2026" was true on that date. It is not a price target or a view on the share.
- Never a recommendation. Companies and funds are named to make an example concrete. None of them has paid to be mentioned. See About.
Found a figure that doesn't reproduce? Tell me, with the page and the number.