How it works
The people at the top table and any children at a separate table come off the total; everyone else is split into tables of the size you choose, rounding up. If there are seats to spare, it's better to spread them out (several tables with one person fewer) than to leave one table half empty.
Each venue decides its own table size: ask how many people fit comfortably at theirs. And for working out who sits where, there's our guide on how to plan your wedding seating.