Investment Calculator

This investment calculator shows what a starting amount plus regular contributions can grow to. Example: 10,000 plus 200 a month at 7% a year becomes 140,204.12 after 20 years – 58,000.00 paid in and 82,204.12 growth.

Source: Brealey/Myers/Allen: Principles of Corporate Finance – Endwert gleichbleibender Zahlungen; Darstellung: Wikipedia „Time value of money“. Updated: 4 October 2026.

Starting amount

Monthly contribution

Expected return

% per year

Effective annual return after costs. A negative value models a loss.

Investment period

years

Contributions are paid

Target amount (optional)

Shows the contribution, return or time needed to reach it. Leave at 0 to skip.

My ToolboxYour inputs are saved in this browser only.

Result

Result: Final balance 140,204.12 · paid in 58,000.00 · growth 82,204.12
Reaching your target: Three ways to reach 200,000.00 Needed
Monthly contribution (other inputs unchanged) 317.82
Annual return (other inputs unchanged) 9.61% per year
Investment period (other inputs unchanged) 24.3 years
Balance year by year: Year Paid in Growth Balance
1 12,400.00 776.06 13,176.06
2 14,800.00 1,774.44 16,574.44
3 17,200.00 3,010.71 20,210.71
4 19,600.00 4,501.52 24,101.52
5 22,000.00 6,264.69 28,264.69
6 24,400.00 8,319.28 32,719.28
7 26,800.00 10,685.69 37,485.69
8 29,200.00 13,385.74 42,585.74
9 31,600.00 16,442.80 48,042.80
10 34,000.00 19,881.86 53,881.86
11 36,400.00 23,729.65 60,129.65
12 38,800.00 28,014.78 66,814.78
13 41,200.00 32,767.88 73,967.88
14 43,600.00 38,021.69 81,621.69
15 46,000.00 43,811.27 89,811.27
16 48,400.00 50,174.12 98,574.12
17 50,800.00 57,150.36 107,950.36
18 53,200.00 64,782.95 117,982.95
19 55,600.00 73,117.81 128,717.81
20 58,000.00 82,204.12 140,204.12
Working: Monthly rate: (1 + 7%)^(1/12) − 1 = 0.5654%.
Starting amount: 10,000.00 × (1 + 7%)^20 = 38,696.84.
240 contributions of 200.00, each at month end, grow to 101,507.28.
38,696.84 + 101,507.28 = 140,204.12; 58,000.00 of that was paid in, 82,204.12 is growth.; The target of 200,000.00 is missed by 59,795.88. A projection with a constant return, before taxes, fees and inflation. Real investments fluctuate and can lose value. Pure arithmetic, not investment advice.

Three ways to reach 200,000.00	Needed
Monthly contribution (other inputs unchanged)	317.82
Annual return (other inputs unchanged)	9.61% per year
Investment period (other inputs unchanged)	24.3 years

Year	Paid in	Growth	Balance
1	12,400.00	776.06	13,176.06
2	14,800.00	1,774.44	16,574.44
3	17,200.00	3,010.71	20,210.71
4	19,600.00	4,501.52	24,101.52
5	22,000.00	6,264.69	28,264.69
6	24,400.00	8,319.28	32,719.28
7	26,800.00	10,685.69	37,485.69
8	29,200.00	13,385.74	42,585.74
9	31,600.00	16,442.80	48,042.80
10	34,000.00	19,881.86	53,881.86
11	36,400.00	23,729.65	60,129.65
12	38,800.00	28,014.78	66,814.78
13	41,200.00	32,767.88	73,967.88
14	43,600.00	38,021.69	81,621.69
15	46,000.00	43,811.27	89,811.27
16	48,400.00	50,174.12	98,574.12
17	50,800.00	57,150.36	107,950.36
18	53,200.00	64,782.95	117,982.95
19	55,600.00	73,117.81	128,717.81
20	58,000.00	82,204.12	140,204.12

How it is calculated

An investment calculator applies compound growth to two things: the money you invest today and the contributions you add along the way. Each amount earns a return, and the return itself keeps earning – which is why the last years of a long investment add the most.

Formula

FV = P × (1 + i)ⁿ + C × ((1 + i)ⁿ − 1) ÷ i, with starting amount P, monthly contribution C, n months and the monthly rate i = (1 + annual return)^1/12 − 1. If contributions are paid at the start of the month, the second term is multiplied by (1 + i).

Worked example

10,000 today, 200 a month, 7% a year, 20 years: the starting amount alone grows to 38,696.84, the 240 contributions to 101,507.28. Together that is 140,204.12, of which 58,000.00 was paid in and 82,204.12 is growth. After 10 years the balance is only 53,881.86 – the second decade adds far more than the first. Paying at the start of each month lifts the result to 140,778.06.

Working backwards from a target

Enter a target and the calculator solves the same equation for one unknown at a time. To reach 200,000 in the example you could raise the contribution to 317.82 a month, earn 9.61% a year instead of 7%, or simply keep going for 24.3 years. With the inputs as they are, the target is missed by 59,795.88.

The return is an assumption, not a promise – run a cautious and an optimistic case.
Inflation reduces what the final balance will buy; subtract it from the return to think in today’s money.

Frequently asked questions

How much will my investment be worth?

It depends on amount, time and return. 10,000 plus 200 a month at 7% grows to 140,204.12 in 20 years; at the same return but only 10 years it is 53,881.86.

How much do I need to invest each month to reach a goal?

Enter the goal as the target amount. For 200,000 in 20 years at 7%, with 10,000 already invested, the answer is 317.82 a month.

What return do I need?

The target table shows the annual return that would turn your inputs into the target – 9.61% in the example. If that looks unrealistic, a higher contribution or a longer period is the safer lever.

Does it matter when in the month I invest?

A little. Paying at the start of each month gives every contribution one more month of growth: 140,778.06 instead of 140,204.12 in the example.

Is the result guaranteed?

No. The calculation assumes the same return every year. Markets rise and fall, and taxes and fees reduce what you keep.

Sources and legal basis

As of: 4 October 2026 · Editorial policy