Previous researchers studied the behavior of Ultra-High Performance Concrete (UHPC) columns confined with steel tubes. However, predicting the influence of the confinement effect and the compressive capacity of these columns has yet to be further examined. Currently, the Canadian design code limits for reinforced concrete do not reach the strength nor the strain produced by using UHPC. This project uses the Canadian design methods for a cross-section of UHPC to form a column interaction curve and compared it with six test specimens. The effects of steel tube confinement will also be examined. Additionally, the Eurocode 4 (EC4) method, which includes the strengths of UHPC and confinement of steel tube, was used to formulate another column interaction curve. The results show that the Canadian code severely underestimates the design strength of confined UHPC while the EC4 provides much more accurate results.