The invention shows and describes a grinding method for machining the surface of workpieces (6) with a plurality of inner grinding spindles, comprising the following steps: a) providing a grinding machine (1, 1') with at least two grinding tools (2, 2'), wherein the grinding tools (2, 2') are each mounted to rotate about a grinding tool axis (X2, X2'), b) providing at least two workpieces (6) to be machined, c) arranging the workpieces (6) on one of at least two workpiece holders (5, 5', 5") of a workpiece holder unit (4), wherein the at least two workpiece holders (5, 5', 5") are each mounted to rotate about a workpiece holder axis (X5), and wherein the workpiece holder unit (4) is mounted to rotate about a workpiece holder unit axis (X4), and d) grinding the workpiece surfaces (8) of the workpieces (6), wherein the grinding tools (2, 2') rotate about the grinding tool axes (X2, X2'), wherein the at least two workpiece holders (5, 5', 5") each rotate about a workpiece holder axis (X5), and wherein the workpi
