In this case, the best choice to make is probably a 10mm belt. Those kinds of belts are the most common, and in my opinion, they are the suitable for most lifters, no matter the weight. This is because a 10mm belt is the most balanced, being thick enough to hold a lot of weight, yet being more comfortable and less stiff than a 13mm one.
The second type of belt I recommend is the 13mm thick if you feel like a 10mm is not enough for you or you lift huge amounts of weights.
Those belts are more common in a powerlifting competition but this doesn’t mean that you have to be a professional powerlifter to wear one.
If you feel like it’s going to benefit you, it’s completely fine to go with it, but keep in mind that the comfort has to suffer and it’s going to feel stiffer than a 10mm version. The main advantage over a 10mm belt is the increased support it provides.
The proper width range is 4 to 5 inches, which is a good thing because most of the belts on the market are in this range. If I would have to be more specific I would choose the 4-inch wide option, because I believe it’s more than enough for everybody. If you are not sure about this, you can go with a 5-inch wide belt without any worries.