Party Food Portion Calculator
Planning catering quantities is straightforward arithmetic once you decide a per-person portion. This calculator scales any dish by your guest count, a base portion per person, an optional hourly increment for longer events, and a leftover buffer you choose. It returns the per-person total, the total before buffer, the buffer amount, and the grand total to buy. Portion sizes are a host's judgment that depends on the menu and the crowd, so the per-person figures are editable inputs. Run it once per dish to build a complete shopping list.
Portion planning formula
per person = base portion + hourly add * event hours
total before buffer = per person * guests
buffer amount = total before buffer * (buffer % / 100)
grand total = total before buffer + buffer amount
Units are whatever you choose (ounces, servings, pieces); keep them consistent. Set the hourly add to zero for a fixed single-serving plan.
Portion planning notes
- Mains often run roughly 6 to 8 ounces of protein per adult as a planning guide.
- Grazing and drinks scale with event length; use the hourly add.
- A 10 to 20 percent leftover buffer is common.
- Portion sizes depend on the menu and crowd; adjust to taste.
- Run once per dish to build a full shopping list.
Party portions: frequently asked questions
How much food per person should I plan?
Per-person portions are a host's judgment based on the dish and the event. As a rough planning figure, mains often run around 6 to 8 ounces of protein per adult, plus sides. Because appetites and menus vary, the per-person amount is a user-editable input; enter the figure for each dish you are planning.
How does event length change quantities?
Longer events mean more eating, especially for grazing food and drinks. This calculator lets you add a per-hour increment per person, so a four hour party plans more than a one hour drop-in. Set the hourly add to zero for a fixed single-serving plan.
Should I plan for leftovers?
Many hosts add a buffer so they do not run out. The leftover buffer here is a percentage you choose, applied on top of the base quantity. A 10 to 20 percent buffer is common; raise it if guests may bring extras or if you want planned leftovers.
How is the total amount calculated?
Total per person equals the base portion plus the hourly add times event hours. Multiply by the number of guests, then apply the leftover buffer. The calculator also shows the per-person total and the buffer amount so you can see how the parts combine.
Can I use this for drinks too?
Yes. Treat each beverage as a dish: enter servings per person per hour as the hourly add, set the base to the first round, and the same math applies. Run the calculator once per item to build a full shopping list.
Official sources
- USDA: FoodData Central (serving sizes).
- USDA: Food Safety and Inspection Service (safe handling for crowds).
Reviewed by the CalculatorHub team, edited by James Graham, 17 June 2026. See our methodology.