Changes in the thickness of the dermis and epidermis have been described in the scenario of tissue expansion as well as inflammatory skin processes (psoriasis, contact hypersensitivity and so on). These changes have previously been quantified by using ocular micrometers to obtain and then average a limited number of spot measurements, leading to suboptimal accuracy. We describe a rapid method of using freely available Image J software to analyze digitized images of fixed skin specimens. By determining the cross-sectional area and surface length of a skin layer, a simple calculation produces more accurate and reproducible measurements of its thickness compared to historical methods, with excellent inter-rate reliability. This article is protected by copyright. All rights reserved.