Approximately 135 x 77 x 34. I think it's okay even for a first-time natural whetstone user. If you go straight from a medium grit, you'll need to spend a lot of time to remove the scratches, so please use this as an intermediate stone. It also has a good thickness, so if you use it for finishing, it should last a long time. It's also quite sharp, with a bright, cloudy finish.