Graphene demonstrates the excellent tribological properties as lubricant additive. It was found that during the friction process the multi-layer graphene nanoplatelets exhibited better interlayer sliding than a few-layer graphene. The multi-layer graphene nanoplatelets can form a thicker lubricating films that results in a lower friction coefficient. Graphene nanoplatelets are especially suited for solid lubrication of highly loaded tribological contacts under extreme conditions where traditional lubricants cannot be applied. Therefore, estimation of the thickness of multi-layer graphene nanoplateles is required for further evaluation of the relationship with tribological properties. We focused this work on evaluation of the accuracy of multi-layer graphene nanoplatelets characterization using the adsorption data. As the aspect ratio d/t of the samples of graphene nanoplatelets normally exceeds 10 and reaches value of 100, the experimental adsorption data can be considered for estimation of multi-layer graphene nanoplatelets thickness.