sketch, not a booking
One stall plan, run against every venue you are considering. A hall does not hold area, it holds rows, so this counts whole pitches rather than square metres, and every room is tried both ways round.
Every type has its own pitch, because they are not the same shape. A food stall needs clearance behind it for the person cooking, an information table is one trestle, a workshop needs people seated around it. Change any of them.
Counts open on a sensible guess. How many you plan for is your decision, not anybody else's.
Each of these comes off the floor of whichever room you put it in, as a strip across one end, which is how a kitchen or a run of tables actually gets laid out.
Almost no hall is one clean rectangle, and it does not need to be. An L shaped room is two parts. A room with a stage cut out of one end is two. Split it the way you would walk it. A curved or angled room gets the largest rectangle that fits inside it, which is what you would lay out anyway, because a 3 by 3 marquee does not bend.
Enter the clear floor, not the area on the hall's website, which counts the stage, the storage and the walls.
Signed out, this list is yours to type. Inside a market day it opens on your contact book, and everyone who ticked a stall is already here.
One box per pitch, numbered within its type. Only sellers who asked for that type appear in its list, and a seller already placed does not appear twice.
This calculator books nothing. It does not set a budget, hold a hall or tell a stallholder anything. It keeps what you typed so you can come back to it.
It counts whole pitches only. Half a stall that fits is a stall that does not.
It will not tell you to squeeze. If a venue will not take the stalls, the honest answers are fewer stalls, a smaller pitch or another venue, and the comparison shows what each one buys.