$1,000/Month at 7% for 40 Years → $2,624,813
Final portfolio value
$2,624,813
Total contributed
$480,000
Investment gains
$2,144,813
Total contributed: $480,000
Investment gains: $2,144,813
Investing $1,000 per month at 7% annual return for 40 years grows to $2,624,813. Total contributed: $480,000. Investment gains: $2,144,813. Free compound interest calculator.
Full interactive calculator
Customize all parameters, compare scenarios, export PDF/CSV
Frequently asked questions
How does compound interest work?
Compound interest earns returns on both your principal and previously earned interest. The formula is FV = P(1+r)ⁿ + PMT·((1+r)ⁿ-1)/r for regular contributions.
What is a realistic annual return for investing?
Historically, a diversified stock portfolio has returned 7-10% annually before inflation. 7% is a commonly used conservative estimate that accounts for inflation adjustment.
What is the Rule of 72?
Divide 72 by your annual return rate to estimate how many years it takes to double your money. At 7%, your money doubles in approximately 10.3 years.
Related calculators
More scenarios
⚠ For educational purposes only. Not financial, tax, or legal advice. Always consult a qualified professional before making financial decisions.