How PortionPal Calculates Food Quantities
Every estimate starts with a disclosed per-adult portion, converts children to adult equivalents, applies one appetite factor and one leftovers factor, then rounds the purchase amount to a practical package.
Core formula
Adult equivalents = adults + (children × 0.6). Base quantity = adult equivalents × the food’s base portion. The light, standard and hearty appetite multipliers are 0.85, 1.0 and 1.2. Optional leftover multipliers are 1.0, 1.1 and 1.25.
Combined menus, drinks and ice
The party menu planner divides one total per selected category among that category’s foods, then applies duration, serving-style, appetite and one visible reserve. The drinks calculator starts at 1.2 litres per adult equivalent, adds 0.35 litres per hour after two hours, and applies rounded weather and outdoor adjustments. Ice uses 18% of drink volume by weight, plus 7% outdoors and 8% in hot weather.
Catering cost ranges
The budget calculator uses a versioned local country-and-service range, rounded city tier and budget factor, then adds only selected options. Results are static planning ranges—not live prices or quotes—because provider, menu, season, tax and service requirements vary.
Planning Guides and shared calculations
Planning Guide tables call the same portion, combined-menu, drinks and budget engines as the calculators. Start with food per person, party food planning, drinks per person or catering cost per person. Guide-specific explanatory ranges name their assumptions and do not override calculator configuration.
Raw weight, cooked yield and units
The calculator labels raw and cooked quantities separately. Pasta uses 100 g dry per adult for a standard main dish or 60 g for a side, then estimates cooked weight at 2.25 times dry weight. Rice uses 3 times dry weight, and the BBQ calculator assumes a 70% cooked yield. US and metric displays convert the same underlying quantity; changing units does not change the formula.
Event type and serving style
Event-specific calculators may distribute demand across appetizers, meals, sides or drinks. Buffets can require a defined service buffer, while plated service allows tighter counts. A multi-item menu must divide demand among dishes so a full portion is not assigned to every item.
Multi-day travel planning
The vacation food planner multiplies age-adjusted portions by the meal occasions covered by groceries, not simply by nights away. Restaurant meals are excluded, while packed and backup meals remain separate. Storage and cooking equipment change suitable foods and shopping frequency rather than changing the base appetite formula.
Package rounding
The calculated quantity and purchase suggestion are separate. Purchase suggestions round upward to a practical package size only after the appetite and leftover adjustment. We do not add a new percentage at every rounding step.
Limits and food safety
These are planning estimates, not nutrition prescriptions. Recipes, age, culture, appetite, event duration, climate and service style can change real demand. Follow product instructions and current official food-safety guidance. For buffets, the FDA’s safe buffet guidance covers hot and cold holding and the two-hour rule.
Corrections and review
Calculator changes require a documented assumption and a test. If an estimate appears wrong, include the calculator URL, guest inputs, selected units and the result in a contact message. Last reviewed: 27 July 2026.