Bending machine for bending a plate-shaped object, having a measurement device (100... 103) disposed in a feed region for the plate-shaped object to be bent, for measuring a thickness (d) of the plate-shaped object, comprising: - a first measurement sensor (21... 23), which is set up for measuring a first position of a contact point of the first measurement sensor (21... 23) with a first surface of the plate-shaped object, characterized by - a second measurement sensor (31... 33), which is set up for measuring a second position of a contact point of the second measurement sensor (31... 33) with a second surface of the plate-shaped object, which lies opposite to the first surface, - a third measurement sensor (41... 43), which is set up for measuring a third position of a contact point of the third measurement sensor (41... 43) with the second surface of the plate-shaped object, - a fourth measurement sensor (51... 53), which is set up for measuring a fourth position of a contact point of the fourth measurement sensor (51... 53) with the second surface of the plate-shaped object, wherein the positions (82... 84) of the contact points of the second, third, and fourth measurement sensors (31... 53) are spaced apart from one another and disposed in a triangle, and - a computer unit, which is set up for calculating the thickness (d) of the plate-shaped object, which corresponds to the normal distance of the first surface from the second surface, on the basis of the first to fourth positions (81... 84), which are measured essentially at the same time, wherein - the measurement sensors (21... 51, 22... 52) each have a linearly displaceable measurement plunger, the displacement directions of which are oriented parallel to one another, and which are a) retractable/extendable and/or b) are set up for measuring at a predeterminable plunger force or a predeterminable plunger pressure. - a first measurement sensor (21... 23), which is set up for measuring a first position of a contact point of the first measurement sensor (21... 23) with a first surface of the plate-shaped object, - a second measurement sensor (31... 33), which is set up for measuring a second position of a contact point of the second measurement sensor (31... 33) with a second surface of the plate-shaped object, which lies opposite to the first surface, - a third measurement sensor (41... 43), which is set up for measuring a third position of a contact point of the third measurement sensor (41... 43) with the second surface of the plate-shaped object, - a fourth measurement sensor (51... 53), which is set up for measuring a fourth position of a contact point of the fourth measurement sensor (51... 53) with the second surface of the plate-shaped object, wherein the positions (82... 84) of the contact points of the second, third, and fourth measurement sensors (31... 53) are spaced apart from one another and disposed in a triangle, and - a computer unit, which is set up for calculating the thickness (d) of the plate-shaped object, which corresponds to the normal distance of the first surface from the second surface, on the basis of the first to fourth positions (81... 84), which are measured essentially at the same time, wherein - the measurement sensors (21... 51, 22... 52) each have a linearly displaceable measurement plunger, the displacement directions of which are oriented parallel to one another, and which are a) retractable/extendable and/or b) are set up for measuring at a predeterminable plunger force or a predeterminable plunger pressure.