Abstract This paper analyzes the size effect for bending loads. The reduction in fatigue properties in loads with a stress gradient is lower than in loads with homogenous distribution. The proposed test conditions for 1.4301 acid-resistant steel in respect of high-cycle fatigue allowed to verify this phenomenon. The tests were performed on a minispecimen and a standard specimen. Vulnerability of the tested material on changing cross-section size of the specimen depending on the type of load (axial, bending) was confirmed experimentally. Analytical calculations of estimating the characteristics other than for the tested cross-section were performed for KHC coefficient and a highly stressed volume model.