Free state (Ⓕ)
Ⓕ, a capital F in a circle, after a tolerance means the requirement applies to the part in its free state, under no force but gravity. It appears on drawings of flexible parts whose other tolerances are checked while the part is held in a restrained condition.
Easily confused with
How to read it
By default, Cogorno’s guide says, all dimensions and tolerances apply in the free state, except on restrained non-rigid parts. Keyence describes non-rigid parts as those, such as rubber or resin parts, expected to deform beyond the drawing’s limits once the stresses from manufacture are released. Cogorno’s guide says restraint may be applied to flexible parts because they distort once the forces of manufacture are removed, and that the restrained condition should simulate the way the part is held in assembly. Keyence adds that the drawing states the part is non-rigid and the conditions, such as the direction of gravity, under which the free-state tolerance holds. The circled F marks the tolerances that apply with the part free. Keyence’s example drawing reads as datum B having a roundness within 5.0 mm in any orientation, free, while the circular runout on the left side applies under the restrained condition.
Also searched as: Ⓕ, free state gd&t, free state symbol.
This explains what a symbol specifies on a drawing. It isn't inspection or design guidance; the drawing and the edition of the standard it cites take precedence.
Look-alikes
Other circled letters are modifiers too: Ⓜ, Ⓛ, Ⓟ and Ⓣ. Unicode encodes this one as Ⓕ (U+24BB) CIRCLED LATIN CAPITAL LETTER F.
Read next
- Next in GD&T symbolsTangent plane (Ⓣ)Ⓣ, a capital T in a circle, after the tolerance in an orientation frame means the tolerance applies to a plane resting on the high points of the surface, not to every point on it. It is an ASME symbol with no ISO counterpart.
- The same shape in AI labels and iconsAI iconAI-generated or AI-changed content. A badge with the letters AI, often in a circle or beside a word such as generated or modified, labels an image, video, sound or text as made or altered with artificial intelligence. The European Union publishes an official set of these icons.
More GD&T symbols
The same shape elsewhere
Browse symbols drawn with circles or letters and numbers.
Sources
- GD&T of Non-Rigid Parts, GD&T Fundamentals, KEYENCE America, GD&T of Non-Rigid Parts
- Geometric Dimensioning and Tolerancing for Mechanical Design: Instructors’ Guide, Gene R. Cogorno, guide to the McGraw-Hill textbook, rev. 10/12/2020, Technical Training Consultants, Chapters 2 and 5, review answers
- GD&T Symbols, GD&T Fundamentals, KEYENCE America, Associated Symbols
- Enclosed Alphanumerics: Range 2460–24FF (code chart), The Unicode Standard, Version 18.0, Unicode Consortium, U+24BB
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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