About Party Planning Calculators

Last updated June 5, 2026

I host more than I probably should, and “how much do I buy for 30 people?” comes up every time. These are my planning calculators — the per-guest amounts are editable rules of thumb, not gospel.

What’s on this site

Right now there are 6 calculators here: Party Drink Calculator, Food Per Guest Calculator, Party Ice Calculator, Cake Servings Calculator, Pizza Calculator, and Coffee for a Crowd Calculator. Each one is a single-purpose tool that shows its formula, lists its assumptions, and runs on any device with no signup.

Why these are different

A lot of calculators are black boxes — you get a number and no way to tell if it’s right. These work the other way around: the formula, the constants, and a worked example sit on the page next to the result, so you can redo the math by hand. No account, no paywall, no signup.

How the math is kept honest

Each formula is shown in full and was independently re-derived and spot-checked against the calculator’s code. Reference values (typical rates, averages, rules of thumb) are labeled as approximate and are editable, so you can put in your own real numbers. Quantities are planning rules of thumb, not catering or safety guidance — adjust for your guests and follow basic food-safety practices when serving.

Found a mistake?

I’d genuinely like to know. Email [email protected] and I’ll fix it.