Compound Interest Calculator

$1000/month at 6% for 30 years grows to $1,009,538

At 6% compound interest with $1,000/month contributions, your monthly investments grow to $1,009,538 over 30 years โ€” earning $649,538 in compound interest.

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Final balance
$1,009,538
After 30 years
Interest earned
$649,538
180% return
Total deposited
$360,000
Your contributions

What $1000/month at 6% for 30 years really means

By investing $1,000 every month for 30 years at 6%, you contribute a total of $360,000. Compound interest then adds another $649,538 โ€” money you earned without working for it. That's a 180% return on your actual contributions.

At 6% interest, money doubles every approximately 12.0 years (the Rule of 72). In the first year you earn $30 in interest. In year 30, you earn significantly more โ€” because you're earning interest on all the accumulated gains from prior years.

This is why time is the most powerful variable in compound interest. Starting 30 years earlier with the same contribution would produce dramatically more than doubling the contribution amount. Use the full compound interest calculator to model your exact scenario, or compare with a high-interest savings account.

Growth over 30 years
BalanceDeposited

Year-by-year breakdown

YearDepositedInterestBalance
Year 1$12,000$397$12,397
Year 2$24,000$1,559$25,559
Year 3$36,000$3,533$39,533
Year 4$48,000$6,368$54,368
Year 5$60,000$10,119$70,119
Year 6$72,000$14,841$86,841
Year 7$84,000$20,594$104,594
Year 8$96,000$27,443$123,443
Year 9$108,000$35,454$143,454
Year 10$120,000$44,699$164,699
Year 11$132,000$55,254$187,254
Year 12$144,000$67,201$211,201
Year 13$156,000$80,625$236,625
Year 14$168,000$95,616$263,616
Year 15$180,000$112,273$292,273
Year 16$192,000$130,697$322,697
Year 17$204,000$150,997$354,997
Year 18$216,000$173,290$389,290
Year 19$228,000$197,698$425,698
Year 20$240,000$224,351$464,351
Year 21$252,000$253,388$505,388
Year 22$264,000$284,957$548,957
Year 23$276,000$319,213$595,213
Year 24$288,000$356,321$644,321
Year 25$300,000$396,459$696,459
Year 26$312,000$439,812$751,812
Year 27$324,000$486,580$810,580
Year 28$336,000$536,972$872,972
Year 29$348,000$591,212$939,212
Year 30$360,000$649,538$1,009,538

Frequently asked questions

How long does $1,000/month take to double at 6%?+

At 6% compound interest, money doubles approximately every 12.0 years (Rule of 72). So your investment would double at around year 12.0, and double again at year 24.0. Over your 30-year period, your contributions will approximately double.

What if the interest rate changes on $1000/month at 6% for 30 years?+

Rate changes dramatically affect the final balance. At 4%, your 30-year result would be approximately $696,363 โ€” $313,175 less. At 8%, it would be approximately $1,500,295 โ€” $490,758 more. The difference grows exponentially over time.

How does monthly vs annual compounding affect the result?+

Monthly compounding (used here) produces slightly more than annual compounding at the same nominal rate. At 6% annually compounded, your 30-year result would be $1,009,538 โ€” compared to $1,009,538 with monthly compounding. The difference of $0 grows larger the longer the time horizon.

Adjust the scenario

Monthly contribution
$1,000/mo
Fixed for this scenario
6.0%
30 years
Adjusted result
$1,009,538
at 6% for 30 years
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