What is the Position symbol in GD&T?

⌖ — Unicode U+2316 (POSITION INDICATOR). It goes in the first compartment of the feature control frame, ahead of the tolerance value.

Does Position need a datum?

Always references at least one datum. Without a datum reference frame the callout is incomplete and the drawing is ambiguous.

What shape is the Position tolerance zone?

A cylinder (or two parallel planes) centred on the true position. Every point of the controlled feature has to lie inside that zone for the part to pass.

Which GD&T controls are in the same group as Position?

Position is one of 3 location controls: Position, Concentricity, Symmetry.

GD&T · Location · ASME Y14.5

Position GD&T Symbol — Meaning and Datum Rule

https://shopmath.org/gdt/position · data verified August 1, 2026

Position (⌖) is a GD&T location control, and its tolerance zone is a cylinder (or two parallel planes) centred on the true position. It always references a datum.

Symbol: ⌖
Unicode: U+2316
Category: Location
Datum: always

Position · GD&T location symbol

⌖

Unicode: U+2316
Datum: always
Zone: A cylinder (or two parallel planes) centred on the true position

The value in the feature control frame is the width or diameter of that zone, in the drawing's units.

What Position Controls in GD&T

The workhorse of the system. Basic dimensions from the datum reference frame fix an exact ideal location, and the tolerance defines a zone around it that the feature's axis or centre plane must stay within. Because a round zone is a diameter rather than a square envelope, position gives about 57 percent more usable area than an equivalent coordinate tolerance.

The Position GD&T Symbol, Zone and Datum Rule

The symbol as it appears in the feature control frame, with the codepoint to type it and the rule it carries.

Position — GD&T symbol, tolerance zone and datum rule
Property	Value
Symbol	⌖
Unicode codepoint	U+2316 (POSITION INDICATOR)
Category	Location controls — Control where a feature sits relative to a datum reference frame.
Tolerance zone	A cylinder (or two parallel planes) centred on the true position
Datum reference	Always references at least one datum. Without a datum reference frame the callout is incomplete and the drawing is ambiguous.
Standard	ASME Y14.5 (cited, not reproduced); ISO 1101
Also called	true position, true position tolerance

The symbol character is the Unicode codepoint used in drawings and CAD annotations; drafting standards render it with defined proportions that the font approximates.

GD&T Controls Related to Position

Position is a location control. Control where a feature sits relative to a datum reference frame. These are the others in that group — the ones a drawing usually chooses between.

GD&T location symbols related to Position
Symbol	Datum	Tolerance zone
Concentricity	always	A cylinder centred on the datum axis, applied to derived median points
Symmetry	always	Two parallel planes centred on the datum centre plane

Ordered as they appear in the feature control frame reference, form through runout, then modifiers.

Sources and Method for the Position GD&T Reference

Position symbol and rulescompiled

Symbols and codepoints: Unicode Character Database (Unicode License v3). Characteristic list cross-checked against NASA MSFC GD&T Basics (public domain). Descriptions written from scratch; no ASME Y14.5 text reproduced.

Verified against Unicode Character Database codepoint check; 98/98 structural checks passed

Compiled from independent public sources that agree cell-for-cell.

Assumptions

The standard is cited, never reproduced: no ASME Y14.5 definitional text, worked example or figure appears on this site. The description above is original prose.
ASME Y14.5 and ISO 1101 differ in places — the ISO system uses the envelope requirement differently and does not carry every ASME modifier. Where a drawing names a standard, that standard governs.
Dataset scope: EXCLUDED: all ASME Y14.5 definitional text, worked examples and figures. Every description on this site is original prose.

Data last verified

August 1, 2026

How this data is built and checked →

How to Cite This Position GD&T Reference

Citation

ShopMath. "Position GD&T Symbol — Meaning and Datum Rule." ShopMath, verified August 1, 2026, https://shopmath.org/gdt/position

BibTeX

@misc{shopmath-gdt-position,
  title        = {Position GD&T Symbol — Meaning and Datum Rule},
  author       = {{ShopMath}},
  year         = {2026},
  howpublished = {\url{https://shopmath.org/gdt/position}},
  note         = {Data verified 2026-08-01}
}

Permanent URL

https://shopmath.org/gdt/position

Common Questions About Position in GD&T

What does Position mean in GD&T?: The workhorse of the system. Basic dimensions from the datum reference frame fix an exact ideal location, and the tolerance defines a zone around it that the feature's axis or centre plane must stay within. Because a round zone is a diameter rather than a square envelope, position gives about 57 percent more usable area than an equivalent coordinate tolerance.
What is the Position symbol in GD&T?: ⌖ — Unicode U+2316 (POSITION INDICATOR). It goes in the first compartment of the feature control frame, ahead of the tolerance value.
Does Position need a datum?: Always references at least one datum. Without a datum reference frame the callout is incomplete and the drawing is ambiguous.
What shape is the Position tolerance zone?: A cylinder (or two parallel planes) centred on the true position. Every point of the controlled feature has to lie inside that zone for the part to pass.
Which GD&T controls are in the same group as Position?: Position is one of 3 location controls: Position, Concentricity, Symmetry.

Every GD&T symbol and modifier