Compound Interest Calculator – Daily, Monthly, Yearly
Project compound interest with daily, quarterly, monthly or annual compounding and optional monthly contributions.
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Daily compound interest and regular deposits
Illustrative projection only; taxes, fees and variable rates are not included.
Choose annual, quarterly, monthly or daily compounding, then enter an initial balance, annual rate, time horizon and optional monthly contribution. The growth view separates what you deposited from estimated interest. More frequent compounding raises the effective yield slightly when the nominal annual rate is fixed.
For an initial $10,000 at 5% for one year with no extra deposits, daily compounding gives $10,000 × (1 + 0.05/365)^365, or about $10,512.67. Monthly contributions are added at the start of each simulated month in this tool, so its output differs from a single-deposit formula.
Daily compound interest formula
A = P(1 + r/365)^(365t), where P is starting principal, r is the annual rate as a decimal, and t is years. The tool also models monthly contributions, which makes the full projection more than this single-deposit formula.
Compare daily, monthly and yearly
Keep the same principal, rate and years, then switch the frequency selector. Compare both the ending value and yearly rows. Interest rates and returns in real investments are not guaranteed.
How It Works
Pexlii’s compound interest calculator visualizes the compounding growth of your money without requiring accounts or transmitting your investment plans over the internet. Unlike cloud-based financial portals that log user net worth scenarios, our algorithm runs entirely client-side. The calculation engine computes two synchronized equations: the geometric growth of your initial principal balance and the accumulated future value of recurring monthly contributions. It adjusts calculations based on your selected compounding frequency—whether interest compounds annually, quarterly, monthly, or daily. For every single year of your investment horizon, the browser tab calculates the exact split between the capital you deposited and the compound returns generated. The interactive ratio bar displays total principal versus earned interest, and the year-by-year schedule can be downloaded as a CSV file. Because all arithmetic runs locally in JavaScript, sliders update instantaneously without network latency.
🔒 Your files and entered content are processed on this device and are not uploaded by this tool. Pexlii also loads Google Analytics for usage measurement; tool events include the tool name, category, and action type, not your files or entered content.
How to Use Compound Interest Calculator
Enter the starting balance, interest rate, duration, and compounding frequency.
Add any recurring contribution and its timing.
Calculate the projected balance and separate contributions from earned interest.
Adjust the assumptions to compare conservative and optimistic scenarios.
Key Capabilities
Application Scenarios
Frequently Asked Questions about Compound Interest Calculator
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