<p>This study investigates the design methods for the overall stability capacity in equal-leg angles under axial compression and those subjected to eccentric compression with single-sided connections. It compares eight current codes from China, Europe, Australia, and the United States, emphasizing the differing design considerations for equal-leg angles. The research is based on 712 sets of axial compression tests and 226 sets of eccentric compression tests with single-sided connections on equal-leg angles, examining the discrepancies between the calculated and tested overall stability capacities as per the codes. The findings indicate significant variations in calculated capacities across the eight codes, with a general inclination towards conservatism in axial compression designs for equal-leg angles. Codes such as AS 4100, AS/NZS 4600, and the general method of EN 1993-1-1 use the axial compression-bending (<i>N–M</i>) interaction equation for eccentric compression, whereas GB 50,017, DL/T 5154, EN 1993-3-1, and the concise method of EN 1993-1-1 use a simplified axial compression formula for eccentric compression. These simplified methods deviate from practical engineering scenarios, especially for single-sided connected eccentric compression equal-leg angles. Following a comprehensive evaluation of the codes and test results, this study suggests a revision to the stability factor in GB 50,017 for axial compression in equal-leg angles. Additionally, it introduces a new design method for the overall stability capacity of single-sided connected eccentric compression in equal-leg angles, drawing on the <i>N–M</i> interaction equation from AS/NZS 4600. The paper concludes with the experimental data validation of the proposed stability factor for axial compression in equal-leg angles and the new design method for eccentric compression in equal-leg angles.</p>