The formula
total = (meal + bar + favour) × guests + fixed costs
Where it comes from
Wedding budgets run away because people read them as a list of items instead of two blocks. One block grows with every guest — the meal, the bar, the invitation, the favour — and the other costs the same for fifty people as for two hundred: the dress, the photographer, the music, the rings. When someone says "we will cut twenty guests" they are only touching the first block, which is why the saving always disappoints. Seeing the two apart also explains the other side: cost per guest goes up when you shorten the list, because the fixed part is shared among fewer people.
How to work it out by hand
- Add up what each guest costs: meal, bar, invitation and favour
- Multiply that by the number of guests
- Add up separately everything you pay once, whoever turns up
- Divide the total by the guests to get the cost per head
What is worth knowing
Set aside five to ten per cent for what is on nobody’s list: the menu tasting, the last-minute extras, transport for guests, tips. And the per-head price venues quote almost never includes the open bar after dinner, which is where a serious chunk of the bill goes.