Transparent math, visible assumptions.

What a published calculator includes

A Food Profit Lab calculator is published only when the calculation works, the input definitions are visible, and the result can be interpreted without hidden context. Each live page is designed to show a direct answer, formula, variable definitions, worked example, assumptions, limitations, and review date.

Calculation logic

Core math lives in pure TypeScript functions separate from the form and page content. That keeps formulas testable and lets future interfaces use the same implementation without copying the math into new components.

• Inputs are validated before a result is returned.
• Invalid states return specific field-level issues instead of a plausible-looking number.
• Intermediate values retain full JavaScript numeric precision.
• Rounding is applied for display, not buried inside the core formula unless a calculation explicitly requires it.

Targets and benchmarks

Food businesses vary by concept, service model, market, menu mix, and cost structure. The calculators avoid presenting one target as universally correct. When a target is needed, you enter it. The page then explains what the comparison means and what it does not establish.

Percentages, margin, and markup

A cost percentage divides a cost by sales or selling price. Profit margin divides profit by selling price. Markup divides profit by cost. Because margin and markup use different denominators, the same percentage does not produce the same price. When a calculator solves for a target margin, it uses price = cost ÷ (1 - target margin). A target must be below 100% for that equation to produce a finite price.

Percentage inputs are converted to decimals for calculation. For example, 30% is calculated as 0.30. A percentage-of-sales fee is applied to the sales generated in that calculation, while a fixed fee remains fixed unless the user changes it.

Units and conversions

Unit conversion happens only within compatible dimensions. The Recipe Cost Calculator can convert mass to mass, volume to volume, or count to count. It does not convert weight to volume because that would require an ingredient-specific density. Supported mass units resolve through grams, supported volume units through milliliters, and count items through each.

Other calculators expose only the units needed for their context, such as grams for a coffee dose and practical fluid-volume units for milk. A package amount and a usage amount must describe the same kind of measure. Food Profit Lab does not infer density, package fill, serving size, or yield that the user has not supplied.

Rounding and discrete quantities

Currency and percentages are rounded for display after the underlying calculation. Small displayed values therefore may not add perfectly when recomputed from already rounded figures. When a result requires a whole sale, transaction, cookie, or package, the input or break-even result is treated as a discrete quantity and rounded in the direction stated on that calculator. Continuous estimates are not silently presented as sellable fractions.

What-if scenarios

A scenario changes only the input named in the comparison and holds the remaining entered assumptions constant. It is a sensitivity check, not a forecast. If a calculator has only a total ingredient cost, it can show the effect of changing that total but cannot identify which ingredient caused the change. Competitor counts and other contextual inputs are not converted into market-share assumptions unless the user explicitly chooses such an assumption.

Examples and interpretation

Worked examples use clearly labeled hypothetical numbers. They demonstrate the formula; they do not represent an average business or promise an outcome. Interpretation focuses on follow-up questions—such as count accuracy, waste, portioning, purchasing, sales mix, or scope—rather than treating one result as a diagnosis.

What the calculators do not know

A result includes only the fields defined on that calculator. It cannot know unentered taxes, payment fees, spoilage, labor burden, discounts, financing, local rules, demand, supplier changes, or every overhead category. It also cannot determine whether a user-selected margin or price is appropriate for a particular market. Use the visible exclusions on the page, reconcile important decisions to business records, and involve an accountant, tax professional, or attorney when the decision requires professional judgment.

Review and corrections

Every calculator displays a last-reviewed date. Material formula or definition changes should update that date and the relevant tests. If something looks wrong, send the page URL, the inputs used, and the result you expected through the contact page.

Methodology last reviewed September 1, 2026.