Quick answer
With monthly compounding, the required monthly saving is P = (FV − PV × (1 + r)^n) × r ÷ ((1 + r)^n − 1), where FV is the target, PV is current savings, r is the monthly return and n is the months to retirement. At zero return it is simply the gap divided by the months. As a rule of thumb, most advisers suggest saving 15% of income for retirement.
The formula in plain terms
Two things grow toward the target: your current savings, which compound for the whole period, and your monthly contributions, each of which compounds for the months remaining after it is paid. The formula adds those two growth paths and solves for the monthly amount that makes their sum equal the target.
The return is an assumption you supply, not a prediction. That distinction matters: change the assumed return and the required saving changes sharply, which is why any honest answer comes with the return stated next to it.
Worked examples
Age 30, retiring at 60 (360 months), no current savings, target ₹2 crore, expected return 10% per year: the required saving is ₹8,848 per month. Over 30 years you contribute ₹31,85,153 and growth supplies ₹1,68,14,847 — more than five times what you put in.
Age 35, retiring at 60 (300 months), current savings ₹5 lakh, target ₹1 crore, expected return 8%: the required saving is ₹6,656 per month. The existing ₹5 lakh does 25 years of compounding work, which is why the figure is lower despite the shorter horizon.
Age 40, retiring at 60 (240 months), no current savings, target ₹12 lakh, expected return 0%: the required saving is ₹12,00,000 ÷ 240 = ₹5,000 per month — a useful check that the formula behaves when growth is absent.
The benchmarks: Fidelity milestones and the 15% rule
Fidelity’s widely used milestones, assuming a 15% savings rate and retirement at 67, are: 1× salary saved by 30, 3× by 40, 6× by 50, 8× by 60 and 10× by 67. They are guideposts, not verdicts — your own target depends on your retirement age and spending — but they are the fastest way to see whether you are roughly on track or far behind.
The 15% rule behind those milestones says: save 15% of pre-tax income each year for retirement, including any employer match. Monthly targets at 15% of take-home pay are: ₹625 a month on ₹50,000 a year, ₹938 on ₹75,000, ₹1,250 on ₹1,00,000 and ₹1,875 on ₹1,50,000 (using the standard 10/15/20% tables). If 15% is out of reach, start lower — even ₹20–₹100 a month builds the habit — and raise the rate when income rises.
Monthly saving by starting age: the $2 million table
Published calculations at a 7% annual return show how steeply the monthly figure rises with starting age for a $2 million target at 62: $750 a month starting at 20, $1,050 at 25, $1,550 at 30, $2,250 at 35, $3,500 at 40, $5,500 at 45, $9,350 at 50 and $20,000 at 55. For retirement at 65 the figures are $600 at 20, $1,200 at 30, $2,700 at 40, $6,800 at 50 and $30,000 at 60.
The pattern is the whole argument in one table: each decade of delay roughly doubles or triples the monthly burden. The figures assume annual compounding and no employer match; a 401(k) match lowers your own contribution, because part of the monthly saving comes from the employer.
Why starting early beats saving more
Compare the first two worked examples: the 30-year-old needs ₹8,848 a month for a ₹2 crore target, while the 35-year-old needs ₹6,656 for a ₹1 crore target. Time is doing different amounts of work in each. The general pattern is stark: starting ten years earlier can cut the required monthly amount by more than half for the same target, because growth, not contributions, supplies most of the final amount over long horizons.
The practical consequence is that the monthly figure is most sensitive to the retirement age you choose and least sensitive to small changes in the target. Delaying retirement by five years lowers the monthly figure twice over: more months of contributions and more months of compounding.
Setting the target: replacement rate and inflation
Most guidance targets retirement spending of 70–80% of pre-retirement income, plus a separate healthcare allowance — one 2025 Fidelity estimate puts healthcare at about $315,000 per couple in retirement. And the target must be inflation-adjusted: a ₹2 crore target in 30 years buys far less than ₹2 crore today. For a target in today’s purchasing power, enter roughly today’s target × (1 + inflation)^years.
Social Security or pension income reduces the target: the monthly figure the formula gives is the saving needed beyond those income sources, so subtract their expected value from the target before solving.
What the figure leaves out
Taxes, fund charges and adviser fees are not deducted, so the required saving is a pre-tax, pre-fee figure. The return is assumed constant; real returns vary year to year, so the figure is a planning guide, not a guarantee. And the calculation assumes contributions continue uninterrupted — career breaks, which are common, raise the required rate for the remaining years.
Common mistakes to avoid
Saving a round number without a target; assuming a high return to make the monthly figure palatable; ignoring inflation; forgetting that the figure is pre-tax; comparing your saving to someone else’s without comparing ages; and treating a projection as a promise.
Related calculators
Use the Retirement Savings Goal Calculator to solve for the monthly figure, and the 401k tool to project a balance forwards.
Frequently asked questions
How much should I save each month for retirement?
It depends on your target, time to retirement, current savings and assumed return. As an example, a 30-year-old starting from zero needs ₹8,848 a month to reach ₹2 crore by 60 at 10% a year. A common rule of thumb is 15% of income.
What formula gives the monthly saving?
P = (FV − PV × (1 + r)^n) × r ÷ ((1 + r)^n − 1) with monthly compounding; at zero return it is the gap divided by the months.
What are Fidelity’s retirement milestones?
1× salary by 30, 3× by 40, 6× by 50, 8× by 60 and 10× by 67, assuming a 15% savings rate and retirement at 67.
How much a month for $2 million?
At 7% a year: about $750 starting at 20, $1,550 at 30, $3,500 at 40, $9,350 at 50 and $20,000 at 55, for retirement at 62.
Does the result include inflation?
No. The target is nominal. For a target in today’s purchasing power, enter the inflation-adjusted figure.
Are taxes and fees included?
No. The figure is pre-tax and pre-fee, so the actual required saving may be higher.
Does an employer match change the figure?
Yes. A 401(k) match means part of the monthly saving comes from the employer, so your own contribution can be lower.
What if my current savings already reach the target?
Then no monthly saving is required for that target and return, and the calculator says so instead of giving a negative figure.
Is the monthly figure guaranteed?
No. It is a projection under a constant-return assumption; real returns vary, so review the plan as circumstances change.
Is this guide financial advice?
No. It explains the math and the benchmarks; a retirement plan should be reviewed by a qualified adviser.