About FinCalc

FinCalc is a small set of focused financial calculators built around the same idea: open the page, type your numbers, get an answer. No accounts, no email gates, no tracking of any kind.

What we offer

• Compound Interest Calculator — future value with optional periodic contributions.
• Present Value Calculator — discount a future amount to today.
• Loan / Mortgage Calculator — monthly payment and full amortization schedule.
• NPV / IRR Calculator — discount-cash-flow analysis for any series.

Principles

• No accounts. Nothing to sign up for.
• No email capture. We don't even ask.
• Client-side math. Your numbers never leave the browser.
• Shareable URLs. Encode your inputs into a hash and send to a colleague.
• Dark mode. Respects your system preference; toggle to override.

Feedback

Spotted a bug, want a feature, or just want to say hi? See the contact page.

About the author

FinCalc is built and maintained by a single developer. It started as a scratchpad for working through textbook finance problems — eventually the scratchpad grew into a small static site, and the site grew into something worth sharing.

There is no company behind FinCalc. No investors, no funding round, no growth team. The domain registration, hosting (Cloudflare Pages), and maintenance all come out of one person's pocket. That is intentional: keeping the operating cost near zero is what lets us promise zero tracking and zero ads.

The whole codebase — HTML, CSS, and JavaScript — fits in a handful of files totaling well under 100 KB. You can read it end-to-end in an afternoon. Every line is on purpose; there is no analytics SDK, no A/B testing framework, no obfuscated bundle.

Why these calculators

The four calculators cover the core time-value-of-money toolkit: a future-value tool with periodic contributions, a present-value discount tool, a loan amortization tool, and a general cash-flow NPV / IRR tool. They share the same input conventions and currency formatting so you can move between them without re-learning the interface.

What is missing on purpose: there is no retirement planner, no mortgage comparison, no currency converter, no inflation-adjusted view. Each of those is a separate tool with its own caveats, and bolting them onto FinCalc would dilute the focus. If you want one of those and it does not exist here, that is a feature request, not a missing feature.

Open source

The source is available at github.com/zx9597446/fincalc. File issues, read the code, fork it for your own use. No CLA, no contribution agreement, no Discord — just issues and pull requests.