Party & Catering Food Quantity Calculator

Understanding the catering quantity calculator — concept and principle

This calculator gives a first shopping estimate for a buffet-style party: how much main protein and side dishes to prepare, how many canapés, how many drinks and how much ice. It is meant for home hosts and small caterers who need a quick starting point before writing a menu.

Each per-guest rule of thumb is simply multiplied by 30 guests.

How it is calculated

Main protein (kg) = guests × 0.15 (about 150 g per person).
Sides (kg) = guests × 0.25 (about 250 g per person in total, across all sides).
Canapés = guests × 4 × hours.
Drinks = guests × (2 + max(0, hours − 1)): two in the first hour, one per hour after that.
Ice (kg) = guests × 0.5.

All values scale linearly with the number of guests; only canapés and drinks also depend on the length of the event.

The principle

These are rules of thumb that caterers use because appetite per person is fairly stable over a large group: some guests eat more, some less, and the average evens out. Drinking and snacking are heaviest at the start, when people arrive hungry and thirsty, then settle into a steady pace, which is why the drinks rule front-loads the first hour. Protein and sides are counted per person for one meal and do not grow with time, since a buffet is usually served once.

Worked example

Inputs: 30 guests, 3 hours.
Main protein = 30 × 0.15 = 4.5 kg.
Sides = 30 × 0.25 = 7.5 kg.
Canapés = 30 × 4 × 3 = 360 pieces.
Drinks = 30 × (2 + 2) = 120 drinks.
Ice = 30 × 0.5 = 15 kg.

Each point is the calculator re-run with only “Guests” changed; the gold point is the default example. Change the inputs above and this chart follows your numbers.

Guests	Main protein (kg, ~150 g each)
7.5	1.13
15	2.25
22.5	3.38
30	4.5
37.5	5.63
45	6.75
60	9

How to read the result

The protein figure is the amount served. If you buy meat with bones or skin, or weigh it raw, buy more, because trimming and cooking loss can be considerable. Canapé numbers apply if bites are the main food; when a full buffet follows, many hosts serve fewer. For a meal with several protein choices, keep the total near the same figure and split it between them. Increase quantities for a younger, active crowd or a long evening, and reduce them for a lunch or an event shortly after a meal.

Common mistakes

Multiplying every dish by the full per-person amount, so that five sides become 1.25 kg per guest.
Forgetting non-drinkers and children, or counting them as full adults.
Treating "drinks" as alcohol only; water and soft drinks are needed too.
Buying ice on the day without a cool box to store it.

Keep in mind: These are average estimates, not guarantees. Keep hot food hot and cold food cold, and do not leave perishable food at room temperature for more than about two hours (one hour above 32 °C).

Frequently asked questions

How much food per person for a buffet?

A common range is roughly 400–500 g of food in total per adult, which matches 150 g protein plus 250 g of sides used here.

How many canapés if dinner follows?

Often 3–5 pieces per person before a seated meal, rather than 4 per hour.

Should I round up?

Yes. Running out is worse than having leftovers, so add 5–10% and plan how to store extra food safely.

Sources: USDA Food Safety and Inspection Service, guidance on serving food safely at parties and buffets (the 2-hour rule)

Checked 8 Nov 2026. Typical coverage rates and standard formulas. Always check the product label and local building rules; buy 5–10% extra for waste.

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