I've got 2 kilt belts, one is a 2.25 inch one, and the other is a ranger belt style and 3 inches wide. It doesnt 'seem' as wide because it's a ranger belt.

It's the belt i'm wearing in

http://www.tharkis.com/images/realmenwearkilts.jpg

which doesnt 'seem' wide because of the style of belt. yet it's very comfortable, particluarly on kilts which lack straps / belt loops.