Every wedding budget is two budgets pretending to be one. There are fixed costs, which are the same whether thirty people come or two hundred, and there are per head costs, which are not. Almost every budget that fails does so because the two were added together at the start and then the guest list moved, and almost every budget that holds separates them on the first day.
Ask three suppliers for a price
Fixed costs first, and they are smaller than you think
The photographer, the officiant or registrar, the planner, the cake, the ceremony flowers, the dress and the suits, the music and the venue's base hire are jobs and things rather than quantities. Adding twenty guests changes none of them. Price these first, because they are the part of the budget you can shop for properly, they are the part where quality is most visible on the day, and they are the part you can decide once and stop thinking about.
How much is a wedding? Per head costs decide the total
Food, drink, service, place settings, favours, transport, evening food and the venue's per person package all scale with the guest list, and together they usually make up most of the bill. That is why the single most powerful lever in any wedding budget is the number of people, and why cutting a supplier by a fifth changes far less than cutting the list by a fifth. Work out your per head figure early, multiply it by the list, and the shape of the whole thing appears.
Average wedding cost UK figures: what they are and are not
Published averages are useful as a shape and misleading as a target. They mix a courthouse wedding with a country house one, they mix markets, and they are frequently drawn from surveys of people who were already spending enough to answer a wedding survey. Use them to check that your per head number is not wildly out, and then ignore them, because your budget is decided by your list and your date rather than by anybody else's.
Cheap wedding choices: where a small budget goes furthest
A weekday or off season date, a shorter day, a shared or sit down meal rather than a full silver service dinner, a venue that includes furniture, and a guest list that stops at the people who would notice if they were not there. Those five decisions move more money than any amount of negotiating, and none of them makes the day worse. The things guests remember are the food, whether they were warm, whether they could hear, and whether they were fed on time.
Other questions people ask
What is the right wedding budget breakdown?
Split it by behaviour rather than by percentage: fixed costs that do not move with the guest list, and per head costs that do. Percentage rules of thumb break the moment the list changes.
What does a smaller budget buy?
Mostly a shorter day, fewer guests and a simpler meal, which is a different wedding rather than a worse one. Fixed costs like the photographer barely move, so the saving comes from the per head side.
Are published average wedding costs useful?
As a sanity check on your per head figure, yes. As a target, no: they mix markets, venue types and survey populations, and no real wedding is the average of them.
What does a 10000 wedding budget actually buy?
A real wedding for a smaller number of people, which is the only lever that works at that figure. The fixed costs on this page barely move, so the arithmetic is guest count times the per head cost, and the usual shape is forty to sixty guests with a venue that does not charge a large hire fee on a day other than Saturday.