Calculate how your investment grows over time with compound interest and regular contributions.
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Enter your initial investment, annual interest rate, time period, and compounding frequency. Optionally add monthly or yearly contributions to see how regular investing accelerates growth. The calculator shows your final balance, total contributions, and total interest earned with a visual breakdown and year-by-year table.
Adding regular contributions dramatically increases your final balance. Even small monthly contributions of $100-$500 add up significantly over 10-30 years thanks to compound interest. The earlier you start and the more consistently you contribute, the larger the compounding effect. This is the core principle behind retirement accounts like 401(k)s and IRAs.
Compound interest earns interest on your interest, causing exponential growth over time. The more frequently interest compounds, the faster your money grows. Daily compounding produces slightly more than monthly, which beats quarterly and yearly. Even small differences in rate or compounding frequency add up dramatically over decades.
Savings accounts often compound daily, CDs may compound monthly or quarterly, and bonds typically pay semiannually. Use this calculator to compare how different frequencies and contribution schedules affect your returns. All calculations run entirely in your browser — your financial data is never sent anywhere.