A full-size lightsaber blade is typically somewhere between 32 and 37 inches long. Despite the 4 or 5 inch range between a shorter full size blade and longer full size blade, all of the blade lengths from 32 to 37 inches do appear to be full size when attached to a lightsaber hilt.
Another common lightsaber blade length is 24 inches, which visually appears too short to be full size. A 24 inch blade works well with a youngling saber or shoto saber.
Many saber companies will sell similar lengths of blades. It’s very common to see: 37 inch blades, 36 inch blades and 32 inch blades. Some saber companies will offer other lengths like: 40 inches, 30 inches, 24 inch or even 16 inches. Some saber companies also allow you to select a custom blade length. Additionally, you can always cut down the length of the blade, if you need to. But you can’t add to a blade if it’s too short.
Even though the lightsaber blade length between 32 and 37 inches is commonly considered full length, a full length blade may not necessarily be the appropriate length for you based on: the space where you wield the saber, your height, the balance of the saber, etc. Do you prefer full length lightsaber blades?