How do I estimate dietary requirement percentages?

If you do not have specific RSVP data, common UK estimates are: 10-15% vegetarian, 3-5% vegan, 5-8% gluten-free, and 3-5% dairy-free. For younger demographics, vegetarian and vegan percentages tend to be higher. Always ask guests about their dietary needs when possible.

Should dietary options only be for those guests?

No. Many guests without specific dietary requirements will also choose vegetarian or vegan options if they look appealing. This calculator accounts for the food needed for each dietary group, but consider that some dishes can serve multiple groups — a vegan dish is also vegetarian and dairy-free.

How many dishes should be gluten-free?

Aim for at least 2-3 naturally gluten-free dishes for a standard buffet. Rice dishes, salads, fruit platters, and many meat dishes are naturally gluten-free. Label everything clearly so guests with dietary requirements can easily identify suitable options.

What is the variety factor?

The variety factor adds a buffer to account for uneven consumption across dishes. A factor of 1.15 means preparing 15% more than the mathematical minimum. This helps ensure no single dish runs out early, which is common when guests have strong preferences.

BakeCalcs

Dietary Buffet Calculator

Plan buffet quantities with dietary requirement splits for vegetarian, vegan, gluten-free, and dairy-free guests.

Total Guests

Number of guests to cater for

Event Duration

Dietary Splits

Vegetarian

Vegan

Gluten-Free

Dairy-Free

How We Calculate This

This calculator splits your total guest count into dietary groups based on the percentages you provide. It then calculates the food quantity needed for each group, adjusted for event duration and a variety factor.

The Calculation

Group size = Total guests x Dietary percentage
Food per person = Base amount x Duration adjustment x Variety factor
Group food total = Group size x Adjusted food per person
Dishes recommended = Base dishes + dietary categories

Frequently Asked Questions

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Last updated: March 2026

All calculations are based on standard ratios and conversions. Results may vary with specific ingredients, equipment, and conditions.