Compound Interest Calculator
Calculate investment growth with optional monthly contributions and year-by-year breakdown
Cómo usar Calculadora de Interés Compuesto
- 1
Enter your starting principal
Type the initial lump-sum amount you are investing or have already saved.
- 2
Set the annual interest rate
Enter the expected annual return or interest rate as a percentage.
- 3
Set the investment period
Enter the number of years you plan to let the money grow.
- 4
Choose a compounding frequency
Select daily, monthly, quarterly, or annually to match how your account compounds interest.
- 5
Optionally add monthly contributions
Enter a regular monthly deposit to see how ongoing savings accelerate growth.
Preguntas frecuentes
Is my data safe?
What is the compound interest formula?
Which compounding frequency should I use?
How are monthly contributions handled in the calculation?
Does this calculator account for taxes?
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¿Qué es Compound Interest Calculator?
Calculate how your savings or investments grow over time with compound interest. Supports daily, monthly, quarterly, and annual compounding, plus optional regular monthly contributions to model realistic savings plans. See a year-by-year breakdown of your balance alongside a visual growth chart showing the split between contributions and earned interest. Everything runs entirely in your browser — no account required.
¿Por qué usar Compound Interest Calculator?
- Multiple compounding frequencies — choose daily, monthly, quarterly, or annual compounding to match your actual account.
- Monthly contributions — add regular deposits to model realistic savings or investment accounts, not just lump-sum growth.
- Year-by-year table — see exactly how your balance grows each year, including the split between what you contributed and what interest earned.
- Visual growth chart — a stacked bar chart shows how interest increasingly dominates contributions over time.
- 100% private — no data is ever sent to a server; all calculations run locally in your browser.
Casos de uso de Compound Interest Calculator
Retirement savings projection
Model how much your 401(k) or IRA could be worth at retirement by entering your current balance, expected return, years until retirement, and monthly contribution.
Savings account projection
See how a high-yield savings account grows with regular deposits, and compare the impact of different interest rates.
Investment comparison
Compare investment scenarios side by side — for example, investing $500/month for 30 years at 6% versus 8% — to understand the impact of return differences.
Education fund planning
Determine how much you need to save monthly to reach a college fund target within a specific number of years.
Consejos y buenas prácticas
- 💡The Rule of 72 — divide 72 by your annual interest rate to estimate how many years it takes to double your money (e.g., at 6% your money doubles in roughly 12 years).
- 💡Compounding frequency matters less than you might think — the difference between daily and monthly compounding is usually less than 0.1% annually; what matters most is the interest rate itself.
- 💡Inflation erodes real returns — a 7% nominal return with 3% inflation yields only about 4% in real purchasing power, so consider whether your target rate accounts for inflation.
- 💡Regular contributions compound too — even small monthly additions benefit from compounding, which is why starting early and contributing consistently is more powerful than timing the market.