It is best to compile your wedding guest list immediately after setting your wedding date. The bride and groom, together with their parents, should compile the list to include those listed in The Guest List.
Once you have completed your list, it is time to estimate your expenditures to determine if you have stayed within your budget. A good rule of thumb is to multiply the number of guests you expect to invite by $100 – $200. This is the average amount one expects to pay for one meal with a drink. If you do not plan to have a meal, but opt instead for hors d’oeuvres or finger foods, the amount can be reduced to $45-$100 per guest. This is a rough estimate, depending on what state and region your wedding will occur in.
Additionally, it is a good idea to visit Liquor Service Options, to help you determine you beverage budget.
If you exceed your budget and are required to shrink the guest list, refer to The Guest List for proper elimination etiquette.