Catering Portions Calculator
Calculate catering quantities from guest count, service style, courses, and event length.
Covers protein, sides, drinks, raw buying weights, and staffing.
Catering quantity calculation ensures you have enough food for every guest without wasteful over-ordering. The key variables are guest count, meal type (plated dinner vs. buffet), event duration, and whether the event includes alcohol.
Standard serving estimates by food category:
| Food Type | Per Person (plated) | Per Person (buffet) |
|---|---|---|
| Protein (meat/fish) | 5–6 oz cooked | 6–8 oz cooked |
| Starch (pasta/rice) | 4 oz cooked | 5–6 oz cooked |
| Vegetables | 4 oz | 5 oz |
| Salad (green) | 2 oz | 3 oz |
| Bread rolls | 1.5 rolls | 2 rolls |
| Dessert | 1 portion | 1.5 portions |
The core catering formula:
Total Quantity = Serving Size × Guest Count × Buffer Factor
Buffer factor by event type:
- Plated dinner (exact courses): 1.05 (5% safety buffer)
- Buffet / cocktail style: 1.15–1.20 (15–20% extra)
- Outdoor events in summer heat: 1.20 (food waste and uncertainty)
Why buffet portions are bigger, not smaller
This one is counterintuitive and it is the single most common way people under-order. A plated dinner is portioned in the kitchen, so each guest gets exactly what you decided. At a buffet the guest portions themselves, and they consistently take more than a chef would give them, especially on the first pass and especially for the protein. Plan 6 to 8 oz per head at a buffet against 5 to 6 plated.
Worked example: Buffet reception for 85 guests, serving chicken, rice, and salad:
- Chicken: 7 oz × 85 × 1.15 = 684 oz = 42.8 lbs cooked
- Chicken loses about 30% in cooking, so buy 42.8 ÷ 0.7 = 61.1 lbs raw, and order 63 to be safe
- Rice, dry weight: 85 × 2.5 oz × 1.15 = 245 oz = 15.3 lbs, so order 16 lbs
- Salad: 3 oz × 85 × 1.15 = 293 oz = 18.3 lbs, so order 19 lbs
Beverage planning:
| Beverage | Per Person per Hour |
|---|---|
| Non-alcoholic drinks | 2 glasses |
| Beer or wine, moderate event | 1 drink |
| Full bar event | 1.5 drinks |
| Water (always have extra) | 2–3 glasses |
A standard 750 ml bottle of wine pours 5 glasses. Work out total drinks first, then divide, rather than guessing bottles.
Raw-to-cooked weight conversions
Watch the direction of this arithmetic, because getting it backwards under-orders by more than it looks. Chicken breast loses about 30% of its weight cooking, so you need 1 ÷ 0.7 = 1.43× the cooked weight, not 1.3×. For 100 lbs cooked that is 143 lbs raw, and the difference between those two factors is 13 lbs of chicken you did not buy.
- Chicken breast: loses about 30%, buy 1.43× the cooked weight
- Ground beef: loses about 25%, buy 1.33×
- Roast beef and pork: lose about 25%, buy 1.33×
- Pasta and rice: dry weight roughly 2.5× in cooked weight, so divide rather than multiply
On the cost side. This page asks you for a per-head food budget rather than assuming one, because ingredient prices move every year and vary enormously by country and by region. Anyone quoting you a fixed dollar figure for catering on a web page is quoting a number from whenever they wrote it.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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