The weight of a barbell used for bench press can vary depending on the type of barbell. The most common types are Olympic barbells and Standard barbells. Olympic barbells typically weigh 45 pounds (20 kg), but there are also other Olympic barbells that come in different weights such as 20kg, 15kg, and 13kg.
Either, Standard barbells typically weigh around 20 to 25 pounds (9 to 11 kg). It is worth noting that these are the standard weight for a barbell, but variations can exist based on the brand and model.
Additionally, the weight of the barbell does not include the weight of the collars or any weight plates, so you should consider that when determining how much weight you will be lifting.
It is always important to make sure that the barbell is of good quality, that the sleeves rotate freely before using it for a bench press, and that the barbell collars are tightened properly to avoid accidents.