# What's your number? A business value calculator

**What it does:** you enter about ten numbers from your business and it shows what a buyer might roughly pay, how far that is from the number you would sell for, and the five changes that would close the gap. You can switch on "levers" (hire a salesperson, cut overhead, raise prices) and watch the value move.

**Try it:** https://whatsyournumber.co (works on a phone and installs like an app; nothing you type leaves your device). It is a prototype, not financial advice.

**What it saved:** built overnight from the transcript of a 33-minute phone call with a friend who has sold several companies. It turns an hour-long "what is my business worth" conversation into a 60-second one.

**Shown at:** AI Open House Session 003, 2026-09-25, by Colton Mulligan.

## What you need

| Tool | Cost |
|------|------|
| Claude (Claude Code) | your existing plan |
| A call recorder or transcript (Plaud, Granola, Otter, any) | optional |
| Static hosting (Cloudflare Pages, Netlify, GitHub Pages) | $0 |
| Your own domain | optional, about $12 to $60 a year |

## How it was built

1. A 33-minute call was recorded and transcribed.
2. Then the transcript went to Claude with "build the tool he described."
3. Then Claude pulled public valuation multiples and cited every source on the page itself.
4. Then it wrote the whole tool as one HTML file. All math runs in the browser, so there is no server and no database.
5. Then it wrote an automated test that clicks through the page (219 checks) before anything ships.
6. Then it went live on Cloudflare Pages on its own domain.
7. Then a QA pass on the day of this session caught a panel growing its own scrollbar on laptops, and fixed and re-tested it at six screen sizes in about 20 minutes.

## What we learned

- The framing that makes it land: start from the owner's own number, then show the gap and what closes it (Zillow's "make me move," for businesses).
- Test layouts at many widths from day one, small phones included. Our tests checked the math and the phone layout but not a laptop-only scrollbar.
- Keep the math on the device and say so on the page. Owners will not type real numbers into something that might store them.

## The prompt

```text
Build me a single-page calculator for [MY INDUSTRY] owners, as one self-contained
HTML file with no server and no outside scripts. All math runs in the browser and
nothing the user types is stored or sent anywhere.

Inputs (about 10): [REVENUE, PROFIT, GROWTH RATE, ...the numbers a buyer in my industry cares about].
Outputs:
- a low / midpoint / high value using public multiples for my industry; cite every source on the page
- the gap between that value and "your number," which the user types in
- a set of levers I can switch on and stack (e.g. "hire a salesperson at $X who brings in $Y"),
  each showing its effect on profit and on value
- a ranked list of the five changes that move the value most

Then write a test that checks the math and checks the page at phone, tablet and laptop widths
for anything that scrolls sideways or spills out of its box.
```

## Stack card

```text
WHAT IT DOES:     Shows what a buyer might pay for your business and the five moves that close the gap to your number
AI / MODEL:       Claude (Claude Code)
STACK:            One self-contained HTML file, Playwright tests, Cloudflare Pages, installable phone app
WHERE IT LIVES:   https://whatsyournumber.co and this recipe
COST TO RUN:      About $0 a month to host, plus a domain
TIME SAVED:       Built overnight from a 33-minute call; a valuation conversation in 60 seconds
TIER SHARED:      template (the prompt) plus the live tool
```

Built by Colton: https://builtbycolton.com

From the AI Open House free library: https://aiopenhouse.co/guests/#library