I would say 17 to 19 inches high. That would be the ADA requirements and also a comfort height for everyone else.
If you mean storage bench, it would depend on your intended use & location (inside/outside).
Hi Desmond, Please consider having a look at Ana Whites awesome website. She has plans for building all types furniture and her designs and dimesions are pretty standard. If this idea attached below is not exactly what you want to have a look around her site perhaps there’s a better option to suit your needs. Hope this helps!