Event Budget Calculator
Total cost and cost per head, split between fixed and per-guest items.
Event costs split into two kinds, and confusing them is how budgets go wrong.
How the event budget calculator works
Event costs split into two kinds, and confusing them is how budgets go wrong. Fixed costs — venue hire, entertainment, photography, decoration — do not change with guest count. Per-guest costs — catering, drinks, favors — scale directly.
That split is what makes cost per head fall as the event grows. A hundred guests spreads the venue hire twice as thinly as fifty, so the marginal guest costs far less than the average one. The marginal figure is the one to use when deciding whether to invite ten more people.
A contingency of 10 to 15% is standard, and it is the line most often cut first and regretted. Events reliably produce costs nobody listed.
Formula: total = fixed + guests × per-guest; per head = total / guests
Worked examples
| Inputs | Total cost | Note |
|---|---|---|
| 120 guests | $30,844.80 | about 230 per head |
| Half the guests | $21,302.40 | a higher cost per head |
| No contingency | $27,540.00 | the risky version |
FAQFrequently asked questions
How do I budget for an event?
Split costs into fixed — venue, entertainment, AV — and per-guest — catering, drinks. Then add a contingency.
Why does cost per head fall with more guests?
Because fixed costs spread across more people. The marginal guest costs only the per-guest items.
How much contingency should I hold?
10 to 15%. It is the line most often cut and most often regretted, because events reliably produce costs nobody listed.
What should I use when deciding to invite more people?
The marginal cost, not the average. Ten more guests cost ten times the per-guest figure, not ten times the cost per head.
What is usually the biggest cost?
Catering and drinks together, typically 50 to 70% of the total for a hosted event.
Where these figures come from
- US FDA Food Code — food service guidance — holding and service context behind catering quantities
- US Food and Drug Administration — the federal food regulator
Last checked: September 2026. Portion and spacing figures are standard catering and event-industry conventions, stated on each page.