How much will $100 a month be worth in 10 years?

Investing $100 a month for 10 years means paying in $12,000 in total. At a hypothetical 7% annual return it would grow to $17,105: $12,000 from your contributions and $5,105 from investment growth. At 4% the balance would be $14,670 ($2,670 of growth), and at 10% it would be $19,986 ($7,986 of growth).

At 4% a year

$14,670

$2,670 of that is growth

At 7% a year

$17,105

$5,105 of that is growth

At 10% a year

$19,986

$7,986 of that is growth

4%, 7% and 10% are example rates, not forecasts. Real returns change from year to year and are never guaranteed, and these figures leave out fees, taxes and inflation.

$100 a month for 10 years at different rates of return

Annual return	Final balance	Total contributed	Interest earned
1%	$12,612	$12,000	$612
2%	$13,260	$12,000	$1,260
3%	$13,945	$12,000	$1,945
4%	$14,670	$12,000	$2,670
5%	$15,436	$12,000	$3,436
6%	$16,247	$12,000	$4,247
7%	$17,105	$12,000	$5,105
8%	$18,012	$12,000	$6,012
9%	$18,972	$12,000	$6,972
10%	$19,986	$12,000	$7,986
11%	$21,059	$12,000	$9,059
12%	$22,193	$12,000	$10,193

Assumes no starting balance, a contribution at the end of every month, and a constant rate compounded once a year (an effective annual rate). You pay in $12,000 in every row; only the growth changes, from $612 at 1% to $10,193 at 12%.

Try your own numbers

The calculator starts with this example at 7%. Change the amount, rate or time period, add a starting balance, or switch the compounding, and the result updates as you type.

Balance after 10 years

$17,105

29.8% of that is interest. Your balance is 1.43 times what you put in.

Total contributions

$12,000

Interest earned

$5,105

Growth by year

Contributions
Interest

Year-by-year breakdown

Year	Contributions	Interest	Balance
1	$1,200	$38	$1,238
2	$2,400	$163	$2,563
3	$3,600	$380	$3,980
4	$4,800	$697	$5,497
5	$6,000	$1,120	$7,120
6	$7,200	$1,656	$8,856
7	$8,400	$2,314	$10,714
8	$9,600	$3,102	$12,702
9	$10,800	$4,029	$14,829
10	$12,000	$5,105	$17,105

How much is your money and how much is growth?

At 7%, 10 years is not long enough for growth to overtake what you pay in: growth is 30% of the final balance and the other 70% is your own money. Keep contributing at the same pace and growth would pass contributions during year 19. A different rate moves that point, but not into these 10 years: it would come in year 14 at 10% and in year 33 at 4%.

In year 10 alone, the balance earns $1,076 at 7%. That is less than the $1,200 you add that year, and compares with $38 of growth in year 1.

What if you change the plan?

Each row changes one thing and keeps everything else the same, at the 7% example rate. The comparison is with $100 a month for 10 years, which ends at $17,105.

Change	Final balance	Difference
Keep contributing for 5 more years (15 years in total)	$31,110	+$14,005
Start 5 years later (contribute for 5 years)	$7,120	−$9,986
Contribute $200 a month instead of $100	$34,210	+$17,105
Start with $10,000 already invested	$36,777	+$19,672
Contribute at the start of each month instead of the end	$17,202	+$97
Earn 6% a year instead of 7%	$16,247	−$858

Starting 5 years later means paying in $6,000 less, but the final balance is $9,986 lower. The gap is bigger than the missing contributions because the earliest payments are the ones with the longest time to grow. A return that is one point lower leaves you with $858 less after 10 years, which is roughly what a 1% annual fee would cost.

Working backwards: to reach $25,000 in 10 years at 7%, starting from zero, you would need to invest about $146 a month.

When would the balance reach $25,000?

The table shows the year in which the balance first reaches each amount, assuming the same $100 a month continues for as long as it takes. Years in bold fall within this page's 10-year period.

Balance reaches	At 4%	At 7%	At 10%
$2,500	Year 3	Year 2	Year 2
$5,000	Year 4	Year 4	Year 4
$10,000	Year 8	Year 7	Year 7
$25,000	Year 16	Year 14	Year 12

How this is calculated

The rate is treated as an effective annual rate, so the balance grows by exactly 7% over a full year. The monthly rate that compounds to 7% a year is:

Monthly rate = (1 + 0.07)^1/12 − 1 = 0.5654%

With $100 added at the end of each month for 120 months (10 × 12), the contributions grow to:

Balance = 100 × [1.005654¹²⁰ − 1] ÷ 0.005654 ≈ $17,105

The rates shown here are rounded; the result uses full precision. Of that balance, 100 × 120 = $12,000 is your contributions and the remaining $5,105 is growth. Every other row in the rate table uses the same formula with a different annual rate. The compound interest calculator page explains the formulas in more detail.

Frequently asked questions

How much interest will $100 a month earn in 10 years?

It depends on the rate of return. At a constant 7% a year, $100 a month for 10 years earns $5,105 on top of $12,000 in contributions, for a balance of $17,105. At 4% the growth is $2,670, and at 10% it is $7,986. These rates are examples, not predictions.

How long does it take to reach $25,000 investing $100 a month?

With a constant 7% annual return and no starting balance, the balance passes $25,000 during year 14. For comparison, at 10% it takes until year 12, and at 4% it takes until year 16.

How much do I need to invest each month to have $25,000 in 10 years?

At a constant 7% annual return you would need about $146 a month for 10 years, starting from zero. At 4% you would need about $170 a month, and at 10% about $125 a month.

$100 a month over other periods

Other monthly amounts for 10 years

A single lump sum for 10 years

See all compound interest examples in one table, or start from scratch with the compound interest calculator.