What is Reverse Investment & Reverse Calculator?
Reverse Investment is a goal-first financial planning methodology where you define your desired future target corpus first (such as ₹1 Crore for retirement or a child's college fund in 15 years) and calculate backward to determine the exact monthly SIP installment or one-time lumpsum needed today to achieve it.
A Reverse Investment Calculator is the inverse compounding engine that makes this possible. While a standard SIP calculator tells you "what your money will grow into," this reverse calculator computes "how much you must invest today" by factoring in your target timeline, compounding rates, and living-cost inflation.
1. Target Reverse SIP
Enter your target wealth and timeframe; the tool computes the exact monthly commitment needed to reach it.
2. Actual CAGR Finder
Uncover the true compound annual growth rate of traditional endowment plans and real estate investments.
3. Exact Date XIRR
Solve complex irregular date-wise investments using Newton-Raphson numerical iterations locally in your browser.
How to plan your target investment step-by-step
1 Select calculation mode
Choose between Reverse SIP, Reverse Lumpsum, CAGR Finder, or XIRR Audit depending on your financial goal.
2 Set target corpus & returns
Enter your target wealth goal and estimated annual return rate based on your portfolio asset class.
3 Enable inflation adjustment
Toggle inflation adjustment to scale your future corpus against inflation and preserve real purchasing power.
4 Review & export scenario
Get your required contribution numbers, share scenarios with your advisor, or generate a high-res PDF audit.
How the Calculations Work (Formulas Explained Simply)
Instead of confusing math, here is how the engine breaks down each scenario in plain terms:
1. Reverse Monthly SIP Formula
What it does: Finds how much money you must invest every month to reach your target corpus on your chosen date.
• Mathematical Form: $$M = \frac{FV}{\frac{(1 + i)^n - 1}{i} \times (1 + i)}$$
• Where: $M$ = Required Monthly SIP | $FV$ = Target Goal | $i$ = Monthly Return Rate ($\frac{\text{Annual Rate}}{12}$) | $n$ = Total Months ($\text{Years} \times 12$)
2. Reverse One-Time Lumpsum Formula
What it does: Calculates the single initial amount you need to deposit today so it grows into your target wealth over time.
• Where: If you need ₹10 Lakhs in 10 years at 12% returns, the formula discounts future ₹10 Lakhs back to today's value (~₹3.22 Lakhs).
3. CAGR (True Annualized Growth Rate)
What it does: Reveals the real annual compounded interest rate of insurance policies, fixed assets, or gold schemes.
4. XIRR (Multi-Date Irregular Returns)
What it does: When you invest or withdraw money on random calendar dates, standard CAGR fails. XIRR solves the exact annualized return rate by making the Net Present Value (NPV) of all cash inflows and outflows equal to zero:
Frequently Asked Questions (FAQ)
1. How is a reverse calculator different from a standard SIP calculator?
Standard calculators show what your current investment will become in the future. A reverse calculator works backward; you specify your target goal (e.g. ₹1 Crore) and it tells you exactly how much you need to invest today or monthly to achieve it.
2. What is the Newton-Raphson method used for in XIRR?
The Net Present Value (NPV) equation for irregular cash flows cannot be solved directly. The Newton-Raphson method is a high-speed mathematical iterative algorithm that converges rapidly to find the exact rate of return where the NPV becomes zero.
3. Why should I adjust my goals for inflation?
Inflation reduces the purchasing power of your money over time. If you target ₹50 Lacs in 15 years, it will have much less value than it does today. Activating the inflation adjustment automatically inflates your target corpus to preserve today's purchasing power.
4. How often should I review and rebalance my reverse SIP target?
You should audit your reverse SIP plan annually or whenever you receive a significant salary hike. Increasing your SIP contribution by 10% annually (Step-Up) helps absorb market underperformance without delaying your milestone target year.
5. Why does a 2% higher CAGR drastically reduce my required monthly investment?
Compound interest acts exponentially rather than linearly over long tenures (10-20 years). A jump from 10% to 12% CAGR allows geometric compounding to shoulder a larger share of the target corpus, reducing your direct out-of-pocket monthly outlay.
6. Can I use the XIRR audit tool to evaluate mutual fund CAS statements?
Yes. Simply input each SIP installment or purchase as an Invested (-) debit with its exact date, and your current folio redemption valuation as a Received (+) credit with today's date. The engine computes your true annualized portfolio yield.