GD&T Symbol Reference

Controls how straight a line element or axis must be. Can be applied to a surface element (line straightness) or an axis (derived median line).

Controls the deviation of a surface from a perfect plane. All points on the surface must fall between two parallel planes spaced at the tolerance value.

Controls how close a circular cross-section is to a perfect circle. Each circular element of the surface must independently conform.

Simultaneously controls roundness, straightness, and taper of a cylindrical surface. More comprehensive than circularity.

Controls the variation of a line element along a surface profile. Each cross-section independently evaluated.

The most versatile GD&T control. Can control form, orientation, location, AND size of any surface simultaneously.

Controls how parallel a surface or axis is relative to a datum. The tolerance zone is oriented parallel to the datum.

Controls the angular relationship of a surface or axis at 90° to a datum.

Controls the angular relationship of a surface or axis at any specified angle (not 90°) to a datum.

The most commonly used location control. Defines the allowable deviation of a feature from its true position. Can be applied with MMC for bonus tolerance.

Controls the coaxial relationship of two or more features. Unlike runout, concentricity controls the derived median points rather than the surface.

Controls how symmetrical a feature is relative to a datum center plane. Controls the median points of opposed elements.

Controls the variation of a surface as it rotates about a datum axis. Checks circular elements independently.

Controls ALL surface elements simultaneously — roundness, straightness, taper, and coaxiality along the entire feature length as it rotates.