GD&T · Modifier · ASME Y14.5
Projected Tolerance Zone GD&T Symbol — Meaning and Datum Rule
https://shopmath.org/gdt/projected-tolerance-zone · data verified August 1, 2026
Projected Tolerance Zone (Ⓟ) is a GD&T modifier: its zone is zone projected above the feature. It never references a datum.
- Symbol
- Ⓟ
- Unicode
- U+24C5
- Category
- Modifier
- Datum
- never
Projected Tolerance Zone · GD&T modifier symbol
Ⓟ
- Unicode
- U+24C5
- Datum
- never
Projected Tolerance Zone qualifies another tolerance rather than standing on its own — it appears after the tolerance value or the datum reference it modifies.
What Projected Tolerance Zone Controls in GD&T
Moves the tolerance zone out of the part and into the space a mating stud or dowel will occupy, for a stated projection height. It is the correct control for threaded and press-fit holes, where a small angular error inside the hole becomes a large positional error at the far end of the protruding fastener.
The Projected Tolerance Zone 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.
| Property | Value |
|---|---|
| Symbol | Ⓟ |
| Unicode codepoint | U+24C5 (CIRCLED LATIN CAPITAL LETTER P) |
| Category | Modifiers and material conditions — Change how a geometric tolerance is interpreted or verified. |
| Tolerance zone | Zone projected above the feature |
| Datum reference | Never references a datum. The tolerance zone floats to best-fit the feature, so this control says nothing about where the feature sits relative to anything else. |
| Standard | ASME Y14.5 (cited, not reproduced); ISO 1101 |
| Also called | projected 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.
Sources and Method for the Projected Tolerance Zone GD&T Reference
- Projected Tolerance Zone 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 to Cite This Projected Tolerance Zone GD&T Reference
Citation
ShopMath. "Projected Tolerance Zone GD&T Symbol — Meaning and Datum Rule." ShopMath, verified August 1, 2026, https://shopmath.org/gdt/projected-tolerance-zone
BibTeX
@misc{shopmath-gdt-projected-tolerance-zone,
title = {Projected Tolerance Zone GD&T Symbol — Meaning and Datum Rule},
author = {{ShopMath}},
year = {2026},
howpublished = {\url{https://shopmath.org/gdt/projected-tolerance-zone}},
note = {Data verified 2026-08-01}
}Permanent URL
https://shopmath.org/gdt/projected-tolerance-zone
Common Questions About Projected Tolerance Zone in GD&T
What does Projected Tolerance Zone mean in GD&T?
- Moves the tolerance zone out of the part and into the space a mating stud or dowel will occupy, for a stated projection height. It is the correct control for threaded and press-fit holes, where a small angular error inside the hole becomes a large positional error at the far end of the protruding fastener.
What is the Projected Tolerance Zone symbol in GD&T?
- Ⓟ — Unicode U+24C5 (CIRCLED LATIN CAPITAL LETTER P). It goes in the first compartment of the feature control frame, ahead of the tolerance value.
Does Projected Tolerance Zone need a datum?
- Never references a datum. The tolerance zone floats to best-fit the feature, so this control says nothing about where the feature sits relative to anything else.
Which GD&T modifiers are in the same group as Projected Tolerance Zone?
- Projected Tolerance Zone is one of 8 modifier modifiers: Projected Tolerance Zone, Maximum Material Condition (MMC), Least Material Condition (LMC), Regardless of Feature Size (RFS), Free State, Tangent Plane, Unequally Disposed Profile, Diameter.