Restaurants · Problem-solving calculator
Catering Portion Calculator
Estimate total food quantity for an event from guest count, portions per guest, portion size, and an allowance.
- Free to use
- Runs in your browser
- Level B · Industry formula
- Last reviewed 2026-08-16
Calculator guide
What this calculator helps you solve
Estimate total food quantity for an event from guest count, portions per guest, portion size, and an allowance.
Inputs explained
- Guests — enter the value that applies to your operation or scenario.
- Portions per guest — enter the value that applies to your operation or scenario.
- Portion size (oz) — enter the value that applies to your operation or scenario.
- Extra allowance (%) — enter the value that applies to your operation or scenario.
Formula and methodology
Worked example
For 120 guests, 1.15 portions each, a 6-ounce portion, and 8% extra, plan about 894 ounces, or 55.9 pounds.
How to interpret the result
Use the quantity as a purchasing/planning target, then adjust for menu mix, buffet behavior, demographics, event length, and product yield.
What to keep in mind
- This is a planning model, not a food-safety or nutrition standard.
- Raw purchasing quantities may need yield or cooking-loss adjustments.
Review approach
This calculator uses deterministic arithmetic and performs the calculation locally in your browser. Its value comes from combining multiple operational inputs into a decision-oriented result rather than returning a one-line conversion.
Review standard: Level B · Industry formula. How calculator reviews work.
Frequently asked questions
What decision can this calculator support?
Use the quantity as a purchasing/planning target, then adjust for menu mix, buffet behavior, demographics, event length, and product yield.
How is the result calculated?
Total Quantity = Guests × Portions per Guest × Portion Size × (1 + Allowance %).
Are the assumptions universal?
No. Operational, regulatory, technical, and industry assumptions vary. Use values that apply to your situation and verify professional or regulatory requirements where relevant.
Does CalculateMeasure store the values I enter?
The calculation runs in your browser and does not require sending the entered calculator values to a server to produce the result.