standarddeviationcalculator.net

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Finance

Investment calculator

See what a starting sum and regular contributions could grow to at a steady rate of return, and how much of the final balance is your own money versus growth. Or set a target and find the contribution that reaches it.

Balance after 20 years $300,850.72
Total contributions$130,000.00
Total growth$170,850.72
Growth share of balance56.8%
Rate per period0.5833%
Effective annual rate7.229%
02468101214161820050000100000150000200000250000300000 years $

━ Balance   ┄ Total paid in

YearAddedGrowthTotal paid inBalance
1$6,000.00$919.19$16,000.00$16,919.19
2$6,000.00$1,419.38$22,000.00$24,338.58
3$6,000.00$1,955.73$28,000.00$32,294.31
4$6,000.00$2,530.85$34,000.00$40,825.16
5$6,000.00$3,147.55$40,000.00$49,972.70
6$6,000.00$3,808.82$46,000.00$59,781.53
7$6,000.00$4,517.90$52,000.00$70,299.43
8$6,000.00$5,278.24$58,000.00$81,577.68
9$6,000.00$6,093.55$64,000.00$93,671.22
10$6,000.00$6,967.79$70,000.00$106,639.02
11$6,000.00$7,905.24$76,000.00$120,544.25
12$6,000.00$8,910.45$82,000.00$135,454.70
13$6,000.00$9,988.32$88,000.00$151,443.02
14$6,000.00$11,144.12$94,000.00$168,587.14
15$6,000.00$12,383.47$100,000.00$186,970.62
16$6,000.00$13,712.41$106,000.00$206,683.03
17$6,000.00$15,137.43$112,000.00$227,820.45
18$6,000.00$16,665.45$118,000.00$250,485.91
19$6,000.00$18,303.94$124,000.00$274,789.85
20$6,000.00$20,060.87$130,000.00$300,850.72
Total$120,000.00$170,850.72$130,000.00$300,850.72
Show the working, step by step

  1. Convert the 7.00% annual return, compounded monthly, to a rate per month (contributions are made 12 times a year).

    i = (1 + 0.0700 ÷ 12)^(12 ÷ 12) − 1 = 0.583333% effective annual rate = 7.2290%

  2. Grow the initial amount over n = 12 × 20 = 240 periods.

    $10,000.00 × (1 + 0.005833)^240 = $40,387.39

  3. Add the future value of the $500.00 contributions, paid at the end of each month.

    FV = PMT × ((1 + i)^n − 1) ÷ i = $500.00 × 520.9267 = $260,463.33

  4. Add the two parts.

    end balance = $40,387.39 + $260,463.33 = $300,850.72

  5. Split the balance into what you paid in and what it earned.

    paid in = $10,000.00 + $500.00 × 240 = $130,000.00 growth = $300,850.72 − $130,000.00 = $170,850.72

These results are estimates from the figures you entered. Real returns vary from year to year, and fees and taxes are not included. This is a calculation, not financial advice.

The formula

FV = P(1 + i)^N + PMT × ((1 + i)^N − 1) ÷ i

P is the initial amount, PMT the regular contribution, N the number of contributions and i the return per contribution period. When contributions are made at the start of each period, the second term is multiplied by (1 + i). If the compounding frequency differs from the contribution frequency, the annual rate r compounded n times a year is converted to a rate per contribution period:

i = (1 + r/n)^(n/p) − 1 (p = contributions per year)

A worked example

The default inputs are $10,000 to start, $500 at the end of every month, a 7% annual return compounded monthly, over 20 years.

  1. Monthly rate: i = 0.07 ÷ 12 = 0.58333%. Number of contributions: N = 12 × 20 = 240.
  2. Initial amount: $10,000 × 1.0058333^240 = $40,387.39.
  3. Contributions: $500 × (1.0058333^240 − 1) ÷ 0.0058333 = $500 × 520.9267 = $260,463.33.
  4. End balance: $40,387.39 + $260,463.33 = $300,850.72.

You pay in $10,000 + 240 × $500 = $130,000, so $170,850.72 (57% of the balance) is growth. That share rises the longer the money is left: most of the growth comes in the later years, which the chart shows as the widening gap between the two lines.

Reading the result

  • The rate is an assumption. Markets do not return 7% every year. A sequence of good and bad years with the same average can end with a different balance.
  • The figures are in future money. At 3% inflation, $300,850 in 20 years buys roughly what $166,600 buys today. Use the inflation calculator to convert.
  • Fees and taxes are not included. A 1% annual fee takes the 7% return to about 6%, which is a noticeably lower balance over 20 years.

How long the money is invested matters most

For the same $500 a month at 7% with no initial amount, the balance after 10 years is about $86,500; after 20 years, about $260,500; after 30 years, about $610,000. Doubling the time more than doubles the result because each year’s growth earns growth of its own.

These results are estimates for planning. They are not a forecast of any particular investment and not financial advice.

Investment calculator: the worked example on this page, with its result and chart
Investment calculator: the worked example above, at a glance.

Common questions

How is the end balance of an investment calculated?

It is the future value of the starting amount plus the future value of the regular contributions: FV = P(1 + i)^N + PMT × ((1 + i)^N − 1) ÷ i, with i the return per contribution period and N the number of contributions. $10,000 plus $500 a month for 20 years at 7% compounded monthly comes to $300,850.72.

Does it matter whether I contribute at the start or end of the month?

A little. Money paid in at the start of each period earns one extra period of growth. In the default example, switching to start-of-month contributions raises the balance from $300,850.72 to $302,370.09. Over short periods the gap is small; the bigger lever is how much you contribute and for how long.

What return should I assume?

There is no right figure, and this page does not recommend one. A fixed deposit or bond fund has a lower and steadier return than a stock fund, whose yearly returns swing widely. Try several rates, say a cautious, a middle and an optimistic one, and plan around the cautious result. Subtract fund fees from the rate you enter.

How do I find the monthly amount needed to reach a target?

Choose “Contribution needed for a target”. The calculator grows the initial amount, takes that away from the target, and divides the gap by the annuity factor. Reaching $500,000 in 20 years from $10,000 at 7% needs $882.30 a month.

Is this the same as a SIP calculator?

Yes. A systematic investment plan (SIP) is a fixed monthly contribution to a mutual fund. Set the currency to ₹, the initial amount to 0 and the contribution to your SIP amount. Real fund returns vary month to month, so the result is an estimate, not a promise.

Written and reviewed by our editorial team. Last updated . Method and sources: how these numbers are computed.