How much should I invest every month?

The required monthly investment depends on three factors: the size of your goal, your time horizon, and your expected rate of return. A 1 Crore goal might need around 43,000 per month over 10 years at 12% annual returns, but only about 10,000 per month if you have 20 years.

How does the duration impact my monthly investment?

Time is the biggest factor in compound interest. Increasing your investment duration by just a few years can drastically reduce the monthly amount you need. Starting 5 years earlier can cut your required SIP by nearly half for the same goal.

What is Goal Inflation Adjustment?

The cost of things increases over time. A house that costs 1 Crore today might cost 1.8 Crore in 10 years at 6% inflation. Enabling Goal Inflation Adjustment inflates your target corpus to its future value before calculating your required monthly investment.

What is the Annual Step-Up?

An Annual Step-Up assumes you increase your monthly SIP by a fixed percentage every year as your salary grows. A 10% annual step-up on a 20,000 SIP means 22,000 in year two, 24,200 in year three, and so on. This lets you start with a smaller amount today and still hit your goal.

How does delaying by one year affect my investment?

Delaying your start by even one year can increase your required monthly investment by 10 to 20 percent, depending on the time horizon. The calculator shows the exact cost of delay for your specific goal and return assumptions.

What return rate should I assume for my calculations?

For conservative planning, use 8% for debt-heavy portfolios and 10 to 12% for balanced equity-heavy portfolios. The Nifty 50 has delivered roughly 11 to 13% CAGR over 10-year periods historically. Use the Return Rate Scenarios section in the calculator to compare 8%, 12%, and 15% side by side.

How do current savings affect the required monthly investment?

If you already have savings, the calculator compounds them at your expected return rate and subtracts the future value from your target. This reduces the gap your monthly SIP needs to fill, lowering your required investment.

What is the difference between this and a regular SIP calculator?

A regular SIP calculator takes your monthly investment as input and shows the future value. This calculator works in reverse: you give it the goal, and it finds the required monthly investment. Both use the same compound interest formula, just solving for different unknowns.

Can I use this for retirement planning?

Yes. Set your retirement corpus as the target, your years until retirement as the duration, and your expected post-retirement or pre-retirement return rate. The calculator will show the monthly investment needed. Use the inflation adjustment to account for rising living costs over your working years.

Does this calculator account for tax?

No. The calculator uses pre-tax return assumptions. Actual returns on equity mutual funds are subject to capital gains tax, and debt instruments are taxed differently. Use this as a planning baseline and consult a CA for tax-adjusted projections.

What is a realistic monthly investment amount for a 1 Crore goal?

At 12% expected annual returns over 10 years, you need approximately 43,041 per month. Over 15 years, it drops to about 19,819. Over 20 years, roughly 10,009. The Time on Goals table in the calculator shows these comparisons for your specific assumptions.

Can I use this calculator for goals other than retirement?

Any financial goal works: a house down payment, children’s education, wedding expenses, or building an emergency corpus. Enter the future cost of the goal as your target, set the time horizon, and the calculator gives you the monthly investment needed.

How much does a step-up SIP reduce my starting monthly investment?

For a 1 Crore goal over 10 years at 12% returns, a flat SIP needs about 43,041 per month, while a 10% annual step-up lowers the starting amount to roughly 29,636, a reduction of about 31%. The instalment then grows by 10% every year, so later contributions make up the difference.

How much do existing savings reduce my required SIP?

Existing savings are compounded forward to your goal date at your expected return rate, and that future value is subtracted from your target. For a 1 Crore goal over 10 years at 12%, 10 lakh in existing savings grows to about 31.06 lakh, cutting the required monthly SIP from 43,041 to roughly 29,673.

What happens if I ignore the Goal Inflation Adjustment toggle?

Leaving it off assumes your target corpus never changes in nominal terms, which understates what you actually need. A 1 Crore goal 15 years away is really worth about 2.4 Crore in future rupees at 6% inflation, which raises the required monthly SIP from 19,819 to roughly 47,496.

What return rate should I use for a house down payment goal?

Since a down payment goal usually has a short 3 to 7 year horizon, a debt-leaning assumption of 7 to 9% is more appropriate than an equity-heavy assumption, since there is less time to recover from a bad market year before you need the money.

Can this calculator handle a wedding or education fund goal?

Yes, any target amount and time horizon works. For weddings, a 3 to 8 year horizon with a 7 to 9% conservative assumption is typical. For a child’s education, a longer 10 to 18 year horizon allows a more balanced 10 to 12% assumption, similar to what the Education Corpus Calculator uses.

Why does my required SIP look different from a plain SIP calculator’s reverse math?

Both use the identical compound interest formula, so the numbers should match exactly for the same inputs. A mismatch usually means a different compounding assumption (monthly versus annual) or a different existing-savings and step-up configuration between the two tools, not an error in either calculator.

Does the required monthly investment change if I invest quarterly instead of monthly?

This calculator solves specifically for a monthly instalment. A quarterly investment of the same annual total generally requires a slightly higher per-instalment amount, since the money invested compounds for fewer, larger sub-periods rather than smaller, more frequent monthly deposits.

Fermor is a financial platform for India. The calculators are the distribution layer: free tools that answer real financial questions with clear math. The product being built is an automated financial action system using the Account Aggregator framework to connect real accounts and close the gap between knowing and doing.

Monthly Investment Calculator: How Much to Invest

Time Horizon	Required Monthly Investment
5 Years	₹1.21 L / month
10 Years	₹43,041 / month
15 Years	₹19,819 / month
20 Years	₹10,009 / month

What Is a Monthly Investment Calculator?

A monthly investment calculator works backward from a target amount to tell you the fixed monthly SIP needed to reach it, given a tenure and an assumed rate of return.

A traditional SIP calculator asks "how much will my monthly investment grow into?" This tool asks the reverse question: "how much do I need to invest every month to reach my target corpus?" Both use the same underlying compounding math, just solved for a different variable.

Required SIP Formula: How It Is Calculated

The calculator starts from the standard SIP future value formula and rearranges it to solve for the monthly instalment (P) instead of the maturity value (M).

P = M / {[((1 + i)^n − 1) / i] × (1 + i)}

Required SIP formula variables
Variable	Meaning
P	Required monthly investment (what this calculator solves for)
M	Target corpus you want to reach
n	Number of monthly instalments (years × 12)
i	Monthly rate, the annual rate divided by 12 and by 100

Worked example: to reach a ₹1 crore goal in 10 years assuming a 12% annual return, solving this formula gives a required monthly SIP of approximately ₹43,041, with no existing savings and no step-up.

Monthly Investment Required for Common Goals

Assuming a 12% expected annual return over 10 years, with no existing savings and no step-up:

Monthly SIP required for common goal amounts
Goal Amount	Required Monthly SIP
₹10 Lakh	~₹4,304
₹25 Lakh	~₹10,760
₹50 Lakh	~₹21,520
₹1 Crore	~₹43,041
₹2 Crore	~₹86,082
₹5 Crore	~₹2,15,206

How Sensitive Is the Required SIP to Your Return Assumption?

The assumed rate of return has a large effect on the required monthly SIP, since a higher return means each rupee invested does more compounding work over the same tenure. For a ₹1 crore goal over 10 years, with no existing savings:

Required monthly SIP by assumed annual return, Rs 1 crore goal over 10 years
Assumed Annual Return	Required Monthly SIP
8% (conservative, debt-leaning)	~₹54,299
12% (balanced equity assumption)	~₹43,041
15% (aggressive equity assumption)	~₹35,886

A higher assumed return lowers the required SIP on paper, but assuming a rate you cannot realistically sustain is the most common way this kind of calculation goes wrong. Use the SIP Calculator to sanity-check a rate against a fund's own real historical returns before committing to it.

How Investment Duration Impacts Contributions

Delaying your investment journey increases the monthly burden non-linearly, not just proportionally. As shown in the "Cost of Delay" card above, missing just one year of early compounding forces a meaningfully larger monthly contribution later, since the money that would have been invested and compounding is simply gone from the timeline. Starting early lets the market fund a larger share of the goal instead of your salary.

Step-Up SIP and Inflation-Adjusted Goals

The Step-Up option increases your monthly instalment by a fixed percentage every year, typically matching expected salary growth, which lowers the starting SIP amount compared to a flat contribution for the same goal. The Inflation Adjustment toggle instead scales up the target corpus itself, so a ₹1 crore goal 15 years from now is treated as needing to be worth ₹1 crore in today's purchasing power, not ₹1 crore in nominal, inflation-eroded rupees. Run the target through the Inflation Calculator first if you are unsure what inflation rate to assume.

How Much a Step-Up SIP Lowers Your Starting Investment

A step-up SIP raises the monthly instalment by a fixed percentage every year, so the starting contribution can be meaningfully lower than a flat SIP for the exact same goal, since later, larger instalments make up the difference.

Required starting SIP with and without annual step-up, Rs 1 crore goal, 10 years, 12% return
Annual Step-Up	Starting Monthly SIP
0% (flat SIP)	~₹43,041
10% per year	~₹29,636

A 10% annual step-up cuts the starting SIP by roughly 31% for the same 10-year, 12% return goal, since the instalment keeps growing every year alongside a typical salary increment.

How Existing Savings Reduce Your Required Monthly Investment

Any lumpsum you already hold gets compounded forward to the end of your tenure at your expected return rate, and that future value is subtracted from your target before the required SIP is calculated. A larger head start means a meaningfully smaller monthly burden.

Worked example: for the same ₹1 crore goal over 10 years at 12%, ₹10 lakh in existing savings grows to roughly ₹31.06 lakh by year 10, cutting the required monthly SIP from ₹43,041 to about ₹29,673, a reduction of nearly 31%.

Why Ignoring Inflation Understates Your Real Requirement

A goal that costs ₹1 crore today will cost more by the time you actually need the money, since prices rise every year. Turning off the Goal Inflation Adjustment toggle silently assumes the target never changes in nominal terms, which understates what you will actually need to save.

Worked example: a ₹1 crore goal 15 years away, inflated at 6% a year, is really a ₹2.4 crore goal in future rupees. That changes the required monthly SIP from ₹19,819 (ignoring inflation) to roughly ₹47,496 (inflation-adjusted), a difference large enough to derail a plan that never accounted for it.

Monthly Investment Required for Common Life Goals

Different goals suit different time horizons and risk levels, which changes the realistic return assumption to use. These are illustrative starting points, not fixed rules.

Typical time horizon and return assumption by financial goal type
Goal	Typical Horizon	Common Return Assumption
House down payment	3-7 years	7-9% (debt-leaning)
Child's higher education	10-18 years	10-12% (balanced)
Wedding expenses	3-8 years	7-9% (debt-leaning)
Retirement corpus	15-30 years	10-13% (equity-heavy, early years)
Emergency fund top-up	1-3 years	5-6.5% (liquid/debt fund)

A shorter horizon calls for a more conservative return assumption since there is less time to recover from a bad market year. For education and retirement specifically, the Education Corpus Calculator and Retirement Calculator add goal-specific detail this general-purpose tool does not.

Limitations of This Calculator

Assumes a constant return rate: real markets do not deliver the same return every year. The final corpus from an actual SIP will differ from this projection based on the sequence of returns, not just the average.

Ignores tax on gains: the target corpus shown is pre-tax. Equity mutual fund gains are taxed on redemption, which reduces the amount actually available to spend.

Step-up assumes uninterrupted increases: a career break, job loss, or pay cut would mean the step-up percentage is not actually sustained every year as modelled.

How to Use This Monthly Investment Calculator

Enter your target corpus: the amount you want to have by the end of the tenure.
Set the tenure and expected return: how many years you have and the annual return you are assuming.
Add any existing savings: a lumpsum you already have reduces the monthly SIP needed.
Turn on step-up or inflation adjustment if relevant: and read the required monthly SIP in the result panel.

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Frequently Asked Questions

A Monthly Investment Calculator is a reverse-engineered SIP calculator. Instead of telling you what your monthly investment will grow into, you input your end goal, time horizon, and expected return rate, and it tells you exactly how much you need to invest every month to reach that target.

Disclaimer: This calculator solves for the monthly SIP required to reach a target corpus, assuming a constant annual return sustained every year of the tenure. Actual investment returns fluctuate year to year and are not guaranteed. Figures shown are pre-tax and do not account for fund expense ratios. This calculator is for educational and planning purposes only and does not constitute financial advice. Consult a SEBI-registered investment adviser before making investment decisions.

CAs can generate detailed Tax Optimization Reports for clients at ca.fermor.in.

Monthly Investment Calculator

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