As of 13 August 2026, AI can calculate party food quantities.

What to actually do

1. Do it yourself

   The route this page recommends

   A chat interface, no skill needed, and roughly 15 minutes until you can act on the result.

   How to actually do it

   1. Count the adults and children attending, separating anyone likely to eat substantially less or more than an average portion.
   2. Write down the complete menu, including canapes, sides, bread, sauces, dessert and drinks, and paste any recipe yields or packet serving information.
   3. Record dietary requirements, allergies, buffet or plated service, serving duration, food already available and the amount of leftovers you want.
   4. Paste the completed details and the copyable prompt into a chatbot, then answer its follow-up questions before accepting the calculation.
   5. Open the relevant recipe pages and food packets, and compare their stated yields and serving sizes with the model's assumptions.
   6. Convert the required amounts into actual supermarket packs, remove duplicate ingredients from the shopping list and add only the items you have decided to provide.
   7. Check the final list against your fridge, freezer and cupboards, then save or print it for the shop and adjust quantities if the guest list changes.

   Prompt

   Calculate the food and drink quantities for my party using the details below. Use UK units and ordinary supermarket pack sizes where possible. Show the assumptions you make, separate adults from children and lighter eaters if that matters, and account for the serving style, dietary requirements, appetite, food already supplied and the amount of leftovers I want. Give me a table with each item, the required amount, a practical buying amount, likely pack sizes and any substitutions needed. Include a consolidated shopping list and flag every detail that could materially change the result. Do not pretend to know missing information: ask concise questions first if the menu or guest information is insufficient.
   
   Party type: [buffet, sit-down meal, barbecue, children's party or other]
   Date and serving time: [details]
   Number of adults: [number]
   Number of children and their ages: [number and ages]
   Expected appetite: [light, average or hearty]
   How long food will be served: [details]
   Menu and recipes, including quantities or yields where known: [paste here]
   Drinks and dessert: [paste details or say not included]
   Dietary requirements and allergies: [details]
   Food already bought or supplied: [details]
   Desired leftovers: [none, a little, or enough for another meal]
   Budget or shop constraints: [details]

   Open it prefilled in ChatGPT or Claude, or copy it into Gemini, which takes no prefill link.

2. Use a tool built for this

   Second choice

3. Hand it to a person

   The distant third

   A person who owns the outcome does this end to end, worth it when the failure is dear.