Monthly Investment Calculator

This monthly investment calculator shows what a regular deposit grows into. With a start amount of 1,000, 200 a month, 20 years and a 6% return minus 0.2% fees, the portfolio reaches about 91,773, of which 49,000 is paid in.

Source: Wikipedia – Future value and annuities. Updated: 30 September 2026.

Start amount

Amount already invested. Any currency works.

Monthly deposit

Years of saving

Return per year (before fees)

Assumed average growth. It is not guaranteed; equity ETFs fluctuate a lot.

Ongoing fees per year

For ETFs, the total expense ratio (TER), often 0.1 to 0.5%. It reduces the return.

Yearly increase of the deposit

If your income rises, you can raise the deposit by this percentage every year.

Fee per deposit

Sales charge or order fee per purchase as a percentage of the deposit. Many plans charge 0%.

Inflation (for purchasing power)

Used to convert the end value into today’s purchasing power. Zero hides the line.

Deposit is paid in at

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Result

Portfolio value at the end: Portfolio value after 20 years: 91,773
Breakdown: Total paid in: 49,000
Growth: 42,773 (47% of the portfolio value)
Purchasing power in today’s money at 2% inflation: 61,760
Return used after fees: 5.8% per year
Growth by year: Year Paid in Growth Portfolio value
1 3,400 121 3,521
2 5,800 389 6,189
3 8,200 811 9,011
4 10,600 1,396 11,996
5 13,000 2,155 15,155
6 15,400 3,097 18,497
7 17,800 4,233 22,033
8 20,200 5,575 25,775
9 22,600 7,133 29,733
10 25,000 8,920 33,920
11 27,400 10,951 38,351
12 29,800 13,238 43,038
13 32,200 15,798 47,998
14 34,600 18,645 53,245
15 37,000 21,796 58,796
16 39,400 25,269 64,669
17 41,800 29,083 70,883
18 44,200 33,258 77,458
19 46,600 37,813 84,413
20 49,000 42,773 91,773
Three scenarios: Return before fees Portfolio value
3 % 65,737
6 % 91,773
9 % 130,234; Model calculation with a constant return and no taxes. Real performance fluctuates and can be negative.

Year	Paid in	Growth	Portfolio value
1	3,400	121	3,521
2	5,800	389	6,189
3	8,200	811	9,011
4	10,600	1,396	11,996
5	13,000	2,155	15,155
6	15,400	3,097	18,497
7	17,800	4,233	22,033
8	20,200	5,575	25,775
9	22,600	7,133	29,733
10	25,000	8,920	33,920
11	27,400	10,951	38,351
12	29,800	13,238	43,038
13	32,200	15,798	47,998
14	34,600	18,645	53,245
15	37,000	21,796	58,796
16	39,400	25,269	64,669
17	41,800	29,083	70,883
18	44,200	33,258	77,458
19	46,600	37,813	84,413
20	49,000	42,773	91,773

Return before fees	Portfolio value
3 %	65,737
6 %	91,773
9 %	130,234

How it is calculated

How the monthly investment calculator works

The calculator assumes an annual return, subtracts ongoing fees and compounds your portfolio every month. Each deposit is paid in at the end (or start) of the month and works from then on. This gives the well-known compounding effect: the gains of the early years earn gains themselves later.

Fees and yearly increases

Ongoing fees (TER) reduce the return every year. 0.2% sounds small, yet over 20 years it costs a few percent of the end value.
Fee per deposit is taken from every payment straight away.
Yearly increase raises the deposit each year, for example in step with pay rises.

Scenarios instead of one number

Nobody knows future returns. The table therefore shows the end value at three percentage points less and more than your assumption. The spread shows how uncertain such a forecast is.

Purchasing power

An end value in 20 years buys less than the same amount today. With the inflation field the calculator converts it into today’s purchasing power.

Honest limits

The calculation uses a constant return and ignores taxes. It is a model, not investment advice.

Frequently asked questions

How do you calculate an ETF savings plan?

With the future value formula for regular payments: each deposit compounds monthly at the return after fees. The calculator does this for you.

What return should I assume?

A cautious figure, such as 4 to 6% a year for a broad equity ETF. The scenario table shows what happens with less or more.

What does 200 a month grow to over 20 years?

At a 6% return and 0.2% fees, about 91,000 with 49,000 paid in, including a start amount of 1,000. It is not guaranteed.

How much do ongoing fees matter?

They reduce the return every year. Over 20 years, 0.2% costs about 3% of the end value, while 1% costs about 15%.

Are taxes included?

No. Taxes on gains and sales depend on your situation and are left out, so the result is a gross value.

Sources and legal basis

As of: 30 September 2026