Reverse Goal Planner
Start from the goal, not the instalment. Enter a target in today’s money and a horizon to see the monthly SIP it takes — with a 10% step-up option.
Starts from the goal instead of the instalment: enter a target and a horizon, and it works backwards to the monthly SIP that reaches it.
How to use it
- Enter the target in today’s money, and the number of years you have.
- Turn on inflation adjustment for anything more than a few years out — otherwise the target is systematically under-funded.
- Add anything you have already saved towards it; the required instalment drops accordingly.
- Compare the three return paths, and consider the step-up option if your income is rising.
How it is calculated
The required contribution is solved from the annuity-due future-value formula for the target, horizon and the modelled return of each path.
Three paths are shown — aggressive, moderate and conservative — each with its own long-run assumed return and the instrument categories that mix implies.
The step-up figure raises the contribution 10% each year and is solved by simulating the whole schedule and binary-searching for the starting instalment that lands on the target.
With inflation adjustment on, the target is grown to what it will cost at the end of the horizon before any of the above runs.
A worked example
What the inflation toggle does to a 15-year goal
- Target in today’s money
- ₹30,00,000
- Horizon
- 15 years
- Inflation adjustment
- Off
- Instalment solved
- Against ₹30,00,000
- Inflation adjustment
- On, at 6%
- Target becomes
- ₹30,00,000 × 1.06^15 ≈ ₹71,90,000
The same goal, priced correctly, needs well over twice the instalment. Leaving the adjustment off does not make the goal cheaper — it funds about 42% of it and discovers the shortfall in year fifteen.
Common mistakes
- Leaving inflation adjustment off for anything more than a couple of years out. It systematically under-funds the goal, always in the same direction.
- Forgetting to enter what is already saved toward the goal, which makes the required instalment look larger than it is.
- Choosing the aggressive path because it produces the smallest instalment. The path is an assumption about returns, not a lever you control.
- Planning several goals independently when they compete for the same monthly surplus — the tool solves one goal at a time and will not flag the conflict.
What it assumes
- Returns are illustrative long-run assumptions per path, not forecasts, and a real sequence of returns will not be smooth.
- It assumes you keep contributing every month for the whole horizon. Interruptions are the most common reason real goals miss.
- It plans one goal at a time. Several goals competing for the same monthly surplus need a priority decision this tool does not make for you.
Frequently asked questions
How much should I invest monthly to reach a goal?
Enter the target in today’s money and the number of years, and the planner works backwards to the monthly SIP required — the reverse of what most calculators do. It solves the annuity-due formula for the contribution, across three modelled return paths so you can see how the answer moves with risk.
What is a step-up SIP and should I use one?
A step-up SIP raises your contribution by a fixed percentage each year, here 10%, on the assumption your income rises too. It lowers the starting instalment substantially for the same target. It suits a rising income and is the wrong choice if your contribution has to stay flat.
Should I adjust my goal for inflation?
Yes, for anything more than a few years away. The planner has an inflation toggle that grows your target to what it will actually cost by the time you get there. A 10-year goal priced in today’s rupees is systematically under-funded, and by a wide margin.