Pour the numbers in. Know your number. Keep the lights on.

Open the app →

The pitch

Every bar owner does this math on a napkin at 1am: rent, payroll, pour cost, drink price — how many pours a night actually keeps this place open?

PRISM CALC does the napkin math for you, live, with a little neon flair. Type five numbers, get your number. No spreadsheet, no login, no nonsense.

What's behind the bar

	Live break-even math Results update as you type — rent, labor, other costs, pour cost, price, days open. Drop a number in, watch the target move.
	A status you can feel Sustainable, Tight, or Unsustainable — color-coded so you know at a glance whether tonight's number is realistic or a fantasy.
	Profit goal, not just survival Nobody opens a bar to break even. Set a monthly profit target and the headline shows what it actually takes to pay yourself.
	Brooklyn neighborhood presets Fifteen neighborhoods, one dropdown. Pick DUMBO or Bed-Stuy and the averages for rent, labor, and drink price pour right into the form.
	Price sensitivity, at a glance A little bar chart shows how the daily target shifts if you bump the menu price up or down a few dollars — before you touch the menu.
	Weekly rhythm Splits the weekly target across Mon–Sun — Even, Typical, or Weekend-heavy — so "258 drinks a week" becomes "~55 on Saturday, ~26 on a Monday." Pick Custom and tap each day's level — Quiet, Normal, Busy, Packed — if the presets don't match your room.
	Text it to your business partner Every scenario lives in the link. Hit Share, send it, they open it and see your exact numbers — no account, no export, no email attachment.

Also on the bar: installable as a phone app that works with no signal, your numbers saved on your own device (nowhere else), and full keyboard/screen-reader support.

The math on the napkin

profit per drink   = selling price − cost to make
monthly costs       = rent + labor + other expenses (+ profit goal, if set)
drinks per day       = (monthly costs ÷ profit per drink) ÷ days open
weekly revenue target = drinks per day × 7 × selling price

No hidden fees, no black box — that's the whole recipe.

Order at the bar

1. Open the app (or install it — see below)
2. Pour in your rent, labor, other expenses, pour cost, and drink price
3. Optional: set a monthly profit goal if break-even isn't the point
4. Watch your daily drinks target land, live
5. Hit Share to send the scenario to a partner, or Reset to start a fresh tab

Prefer a running start? Pick a Brooklyn neighborhood in the sidebar and the form fills itself.

Install it like a real app

On your phone: open the live link, then Add to Home Screen. It opens fullscreen, no browser chrome, and keeps working even if the wifi at the bar is garbage.

Running the bar locally

No build step, no dependencies to install. Fonts come from Google Fonts; everything else is vanilla JS.

python3 -m http.server 8000

Then visit http://localhost:8000. (A plain server keeps the JS modules and service worker happy — opening index.html straight from disk works too, minus offline caching.)

Running the tests

The break-even math is the one thing in this app that has to be right, so it's covered by an automated suite — no framework, just Node's built-in test runner:

npm test

Covers calculator-core.js (validation, break-even/profit-goal math, price sensitivity, weekly rhythm distribution) and the money/integer formatters, including boundary and edge cases: zero and negative inputs, price equal to or below cost, tied peak days, an all-zero custom weekly rhythm, and the always-round-up behavior of the drinks target.

What's under the bar top

BarBreakdownColculator/
├── index.html                     # Page structure
├── manifest.webmanifest           # PWA manifest
├── sw.js                          # Service worker (offline cache; bump CACHE_NAME on deploy)
├── package.json                   # Just "npm test" — no runtime dependencies
├── icons/                         # App icons (512 / 192 / apple-touch)
├── readme-assets/                 # Banner + icons for this README
├── tests/                         # node --test suite for the math
│   ├── calculator-core.test.js
│   └── format.test.js
├── css/
│   └── styles.css                 # PRISM theme (dark neon glassmorphism)
└── js/
    ├── app.js                     # Entry point: form, charts, neighborhoods, persistence, share
    ├── calculator-core.js         # Pure math: validate, compute, price sensitivity, weekly rhythm
    ├── data/
    │   └── brooklyn-bar-data.js   # Embedded neighborhood averages
    └── utils/
        ├── format.js              # Currency/number formatting
        ├── state.js               # localStorage save/restore
        └── ui.js                  # Count-up animation helpers

Restocking the neighborhood data

Edit js/data/brooklyn-bar-data.js. Each entry needs avgCommercialRent, avgDrinkPrice, avgLaborCost, and displayName. These are illustrative estimates, not a market survey — always check against your own lease and payroll.

What's next

There's a short roadmap in ROADMAP.md — day-of-week volume breakdowns, saved scenarios, that kind of thing. No accounts, no backend, no bloat. Last call is early on this one.

License

MIT — pour, remix, and serve however you like.