Bending moment is a measure of the internal bending forces within a structural element, such as a beam or a column, subjected to an external load. It quantifies the tendency of a beam to bend or flex under the applied load. The bending moment at any point along a beam is the algebraic sum of the moments of all the forces acting on one side of that point. The formula for bending moment (M) at a specific point along a beam is given by:

Where:

• $M$ is the bending moment,
• $F$ is the force perpendicular to the beam at the point of interest,
• $d$ is the perpendicular distance from the point of interest to the line of action of the force.