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Home / Compound interest / $100 a month, 30 years

$100 a Month for 30 Years

What does $100 a month become over 30 years? The page starts at 6 percent a year with an empty account. Change any figure.

After 30 years the balance reaches $100,452. Interest supplies $64,452 of it.

$
$
%
years
%
Final balance
$100,452
Total you put in
$36,000
Interest earned
$64,452
Year by year
YearTotal put inBalance
1$1,200$1,234
2$2,400$2,543
3$3,600$3,934
4$4,800$5,410
5$6,000$6,977
6$7,200$8,641
7$8,400$10,407
8$9,600$12,283
9$10,800$14,274
10$12,000$16,388
11$13,200$18,632
12$14,400$21,015
13$15,600$23,545
14$16,800$26,230
15$18,000$29,082
16$19,200$32,109
17$20,400$35,323
18$21,600$38,735
19$22,800$42,358
20$24,000$46,204
21$25,200$50,287
22$26,400$54,623
23$27,600$59,225
24$28,800$64,112
25$30,000$69,299
26$31,200$74,807
27$32,400$80,655
28$33,600$86,863
29$34,800$93,454
30$36,000$100,452
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How the growth is worked out

Turn the yearly return of 6 percent into a monthly rate of 0.5 percent by dividing by twelve. Apply that rate to the balance once a month for 360 months. Add $100 at the end of each month. Nothing else goes into the result.

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Worked example

A monthly deposit of $100 for 30 years comes to $36,000 of your own money. The ending balance is $100,452.

Interest accounts for $64,452. That is 64 percent of the final balance.

Questions about this calculator

How much would $200 a month reach over 30 years at 6 percent?

$200,903 at 6 percent. That is 2 times the balance from $100 a month.

What if the return on $100 a month over 30 years were 5 percent instead of 6?

The balance would be $83,226 instead of $100,452. A return one point higher gives $121,997.

What if you stopped the $100 deposits halfway through 30 years at 6 percent?

After 15 years the balance is $29,082. Left alone for the second half, it would grow to $71,370 instead of $100,452.

What would it take to match $100,452 over 30 years if you started 5 years later at 6 percent?

You would need $144.95 a month for 25 years instead of $100 for 30. Starting early does much of the work.

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This page is for education only and is not financial or tax advice.