Compoundly

Compoundly is a compound interest calculator built for anyone who wants to understand how their money grows over time. No registration, no subscriptions, no cloud sync — everything runs locally on your device.

The core idea is simple: adjust your principal, annual interest rate, time horizon, and compounding frequency using intuitive sliders, and watch the results update instantly. An interactive chart shows the growth curve, making it easy to see the difference between, say, monthly and annual compounding, or the long-term effect of adding a few percentage points to your rate.

Key features:

- Principal, rate, time, and compounding frequency inputs via sliders and direct entry
- Real-time chart visualizing investment growth year by year
- Breakdown of total contributions vs. total interest earned
- Support for multiple compounding frequencies: daily, weekly, monthly, quarterly, semi-annual, annual
- Dark, light, and system theme options
- All calculations happen on-device with no internet required

Compoundly is designed for straightforward use. Open it, enter your numbers, and see the outcome. There are no ads interrupting your session and no account needed to save your settings — everything persists locally.

Whether you are planning a savings goal, comparing investment scenarios, or just curious about the math behind compound interest, Compoundly gives you a clean and responsive tool to explore the numbers.