DREWSKY / WORKING KITCHEN Food · First principles · Useful tools
Drewsky / field lab

A RESTAURANT TOOL / 001

Make the arithmetic visible.
Leave room for the craft.

A recipe begins with ingredients. A business also needs to understand what a sale contributes toward the rest of its costs. This small tool makes the assumptions easy to inspect.

The starting numbers are invented. Use any one currency consistently. Your entries and calculations stay in this browser tab.

The batch and the sale

Use the portions you can actually sell. Trim and batch losses belong in this yield; do not subtract them a second time.

Use revenue retained by the business before the variable fee below. Exclude collected tax and pass-through tips.

For example, packaging. Include each cost once. If you include variable labor here, do not count it again elsewhere.

THE MODEL / PER PORTION

What remains?

Ingredients
—
Variable fee
—
Total variable cost
—
Contribution
—
Contribution as % of net price
—
Ingredient cost as % of net price
—

Calculate to explore the invented example.

Contribution is not net profit. It still has to cover every cost omitted from these inputs, such as remaining labor, rent, utilities, maintenance, and taxes. The fee is a simplified percentage of net price; actual contracts may use a different basis or add fixed fees.

OPEN THE ARITHMETIC
ingredients per portion = batch ingredient spend ÷ saleable portions
fee per portion = net selling price × fee percentage ÷ 100
variable cost = ingredients per portion + other variable costs + fee
contribution = net selling price − variable cost
contribution percentage = contribution ÷ net selling price × 100

Arithmetic uses full precision before display rounding. This is a planning illustration; it does not import records, save prices, or change a menu.

FROM FIRST PRINCIPLES TO SERVICE

One assumption.
One useful test.

The point of the tool is a better question for the next batch.

01 / YIELD

What actually reached the plate?

Compare the planned saleable yield with a measured batch. Keep the original quantity and record what changed.

02 / WORKFLOW

Where did attention go?

Follow one recurring prep or admin task. Observe time, errors, and rework before trying an agent-assisted version.

03 / EVIDENCE

Did the change help?

Compare like conditions and include the review effort. A useful experiment can reveal when a simpler process works better.

Explore simple rules in the artificial-life lab ↗