Building a Free, Open-Source Dividend Calculator Suite

Description and use

The author built a free, no-signup dividend calculator suite running entirely in the browser. The core is an open-source TypeScript library using pure functions, ensuring transparency and eliminating server-side data processing.

Problem

Existing free dividend calculators typically require email signups, trials, or hide their logic behind paywalls, creating friction and lack of transparency for users.

Outcome

A suite of focused dividend calculators (yield, DRIP, monthly income, ETF specific) that runs entirely in the browser with no signup, backed by an open-source, tested TypeScript library.

Workflow

• Identify standard financial formulas (yield, payout ratio, DRIP) as commodity knowledge.
• Create a zero-dependency TypeScript library (dividend-math) containing pure functions for each calculation.
• Implement strict input validation to fail loudly on bad inputs (e.g., NaN) rather than returning plausible nonsense.
• Write unit tests to cover edge cases like zero price or zero earnings.
• Build a static site that imports the library and performs all computations in the browser.
• Publish the library to npm and the source code to GitHub under an MIT license.
• Deploy the static site to ensure no backend data collection is required.

Evidence

Every 'free' dividend calculator I tried wanted an email, a signup, or a trial.

Source

I pulled every formula into one zero-dependency TypeScript library: dividend-math.

Source

It's a statically-generated site — all computation happens in your browser, nothing is sent anywhere.

Source