A dumpy level, builder's auto level, leveling instrument, or automatic level is an optical instrument used to establish or check points in the same horizontal plane. It is used in surveying and building to transfer, measure, or set horizontal levels.

In 1832, English civil engineer William Gravatt, who had worked with Marc Isambard Brunel and his son Isambard on the Thames Tunnel, was commissioned by Mr. H.R. Palmer to examin a scheme for the South Eastern Railway's route from London to Dover. Forced to use the then conventional Y level, during the works Gravatt devised the more transportable and easier to use dumpy level.

The level instrument is set up on a tripod and, depending on the type, either roughly or accurately set to a leveled condition using footscrews (levelling screws). The operator looks through the eyepiece of the telescope while an assistant holds a tape measure or graduated staff vertical at the point under measurement. The instrument and staff are used to gather and/or transfer elevations (levels) during site surveys or building construction. Measurement generally starts from a benchmark with known height determined by a previous survey, or an arbitrary point with an assumed height.