To calculate the number of stalls you need, you should first determine how many horses you will have. If you have two horses, you will need at least two stalls. If you have three horses, you will need at least three stalls and so on. If you think you may add a horse to your herd in the future, it's a good idea to build an extra stall.
In addition to the stalls, you will also need space for a feed room, a tack room, and a wash stall. The feed room should be large enough to store at least a month's worth of hay and grain. The tack room should be large enough to store all of your horse's tack and supplies. The wash stall should be large enough so that you can easily bathe and groom your horse.
The location of your stable is also important. The stable should be in a well-drained area and should be protected from the wind. The stable should also be close to a water source and should have easy access to pasture or other turnout areas.
By carefully planning the size and location of your stable, you can provide your horses with a comfortable and safe environment.