This paper presents the experiments and design formulae of cold-formed plain and dimpled steel columns. A series of compression tests on plain and dimpled channel columns were conducted over a range of different geometries and the strength of the columns were investigated. The change in strength of the dimpled columns resulting from the cold working associated with the dimpling process was considered. The results showed that the buckling and ultimate strengths of dimpled steel columns were up to 33% and 26% greater than plain steel columns, respectively. The test results were evaluated by comparing buckling and ultimate loads of plain and dimpled channel columns with the values predicted by theoretical and semi-empirical methods. It was found that the predicted buckling and ultimate loads correlated well with the experimental results. Based on the experimental results, expressions for determining buckling and ultimate strengths of component plate elements of plain and dimpled channel columns were formulated
