Decision Systems Toolkit

A/B Test Calculator

Everything you need to get started is below.

Use it or keep it

Open the A/B Test Calculator in your browser, or download it to keep.

✔ Includes both English and Chinese versions

✔ Runs locally in your browser

✔ No installation required

Open the A/B Test Calculator in your browser, or download it to keep.

✔ Includes both English and Chinese versions

✔ Runs locally in your browser

✔ No installation required

Open in Browser — English

在线打开 — 中文

Or download a copy:

Version 1.0 · Released July 2026

See the code

This tool is open source.

Every statistical function is written in plain JavaScript you can read and verify.

MIT licensed. Fork it, change it, use it in your own work.

This tool is open source.

Every statistical function is written in plain JavaScript you can read and verify.

MIT licensed. Fork it, change it, use it in your own work.

Systems in Practice

Three examples, three different moments where a test goes wrong.

Example 01

Three add-ons, one test.

Three completely different calls.

Two of them nobody celebrates.

Example 02

One trial-length test.

An 18.6% lift on paper.

A test that was never built to see it.

Example 03

One promotion, eight store types.

Two significant results.

Neither one was real.

Get Future Updates

I'm continuously improving the Decision Systems Toolkit.

If you'd like to hear about new tools, improvements, or future releases, leave your email below

I'm continuously improving the Decision Systems Toolkit.

If you'd like to hear about new tools, improvements, or future releases, leave your email below

(No spam. Product updates only.)

Looking for something more structured?

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A guided implementation program for building a repeatable Career Intelligence System you own.

Built by Grace Ge

Building systems for better decisions.

Decision Systems Toolkit A/B Test Calculator

Decision Systems Toolkit A/B Test Calculator

Decision Systems Toolkit

A/B Test Calculator

Decision Systems Toolkit

A/B Test Calculator