About Us
Why Trust This Calculator?
In a world of black-box algorithms and AI-generated financial advice, transparency matters. Here is exactly how our tool earns your trust:
100% Open Source
Every line of code is publicly auditable on GitHub. You can inspect, verify, and even run the calculations yourself. No hidden logic, no proprietary algorithms.
Formulas You Can Verify
All calculations use standard financial mathematics from authoritative textbooks and institutions. Every formula is documented with its derivation on our Methodology page.
Complete Data Privacy
All calculations run locally in your browser. Nothing is uploaded to a server. We do not collect, store, or share any of your financial data. Ever.
Used Worldwide
This tool serves thousands of users worldwide in English and Chinese — from students learning math to investors planning retirement. Built for accessibility, not profit.
Your Data Stays Yours
Unlike many financial websites, we operate on a zero-data model: no user accounts, no cookies beyond essential functionality, no analytics trackers, no server-side storage. When you enter numbers into our calculators, the computation happens entirely in your browser using JavaScript. Nothing is transmitted over the network. Close the tab, and your data is gone — because it was never ours to keep.
Who Uses This Tool?
Our users range from high school students discovering the power of compound interest for the first time, to experienced investors stress-testing retirement scenarios. Financial educators use it as a classroom demonstration. Freelancers use it to plan irregular income savings. Immigrants use it to compare investment returns across currencies. If you have money and a future, this calculator is for you.
By the Numbers
The Author
WW0099
WW0099 is a software engineer and self-taught personal finance enthusiast. With years of experience building production systems and a passion for financial literacy, they created this calculator to make the mathematics of wealth-building accessible to everyone — not just Wall Street professionals.
- Software EngineerYears of experience building production-grade systems across multiple industries.
- Self-Taught Financial MathematicsIndependently studied through Investopedia, the SEC, the Federal Reserve, and standard financial textbooks.
- Open-Source ContributorEvery line of this calculator's code is publicly auditable on GitHub.
- Peer-Reviewed FormulasThe calculation engine relies on established financial equations — not AI-generated heuristics.
Our Mission
Financial literacy is a superpower. We believe everyone — regardless of income, education, or nationality — deserves free access to accurate financial tools. Our mission is to demystify compound interest and empower people to make informed decisions about their financial future.
Open Methodology
All calculations on this site use standard financial mathematics formulas. We do not use proprietary algorithms, black-box models, or AI-generated financial predictions. Every formula we use is publicly documented on our Methodology page, with references to the original textbooks and institutions that established them.
Frequently Asked Questions
Is this calculator really free?
Yes — completely free, forever. It is open source under an MIT license, so you can even download and run it yourself. There are no subscriptions, paywalls, or hidden fees.
Do you collect my financial data?
No. We operate a zero-data model: no accounts, no analytics trackers, no server-side storage. Every calculation runs locally in your browser. Nothing is transmitted over the network.
How do I know the formulas are accurate?
All formulas come from standard financial mathematics, publicly documented with their derivations on our Methodology page and cross-referenced on our References page. The source code is open on GitHub, so the calculations are fully auditable.
Is this tool a financial advisor?
No. This is an educational calculator. It does not provide personalized investment recommendations, tax advice, or retirement guidance. Please consult a qualified professional before making financial decisions.
⚠️ This calculator is an educational tool, not a financial advisor. While the mathematics is accurate, individual financial situations vary widely. It does not provide personalized investment recommendations, tax advice, or retirement planning guidance. Please consult a qualified professional before making financial decisions. See our full Disclaimer for details.