Black Numbers Law Black Numbers Law

Generational Roadmap

One SIP. Three generations.

Start with what a goal will cost, work back to the monthly investment that funds it, then follow the same corpus through decumulation and on to the two generations that come after.

1

Fund the goal

What monthly SIP reaches your number
Bring this straight across from the Inflation Estimator — it is the inflated cost, not today's cost.
Mirrors the CAGR above — the growth rate this SIP is built on.
The corpus arrives
2

Decumulate — the SWP

Draw a monthly income while the corpus works underneath
Final portfolio balance
Total invested (corpus)
Total withdrawn
Portfolio balance, end of each year
Carried from Stage 1. Editable if you want to sketch a different number.
%
yrs
yrs
Zero for a matured SIP that can draw at once — or set a wait for a late lumpsum that needs time to build first.
%
Stop the yearly increase after a while
This follows the standard SWP method used by most online calculators: each month the withdrawal is taken first, then the remaining balance earns that month's share of the return. The figures line up with what clients see elsewhere. But this assumes returns arrive smoothly every single month — real market yields arrive in lumps, around earnings and payout seasons, not evenly. To stay realistic, it is wiser to enter an expected return about 1% below what you actually anticipate; the smooth-return maths flatters the outcome.
G

Gold, the BNL way

An optional second pot, built from your withdrawals
The BNL 10:10:10 habit Add a gold leg Route a slice of every withdrawal into gold — a second pot growing quietly beside your income.
3

The next two generations

A share is set aside and left untouched to grow for the next generation
A lumpsum, so this uses the full CAGR — there are no staggered instalments to drag it down. On year 21 the same 10 : 10 : 10 withdrawal begins.
Build this plan with BNL →