GD&T Symbol Guide
Regardless Of Feature Size
The default condition where geometric tolerance is independent of the actual feature size.
Definition
Regardless of Feature Size means the geometric tolerance is applied independently of the measured size of the feature.
It is the default condition under GD&T Rule #2 unless MMC or LMC is explicitly specified.
Application
Use RFS when the feature size does not create meaningful extra functional clearance or stock for the controlled geometry.
It is common when balance, centering, or precise relationship must be held consistently at all permitted sizes.
Same Tolerance At Any Accepted Size
RFS is implied unless MMC or LMC is explicitly shown in the feature control frame.
3D Tolerance Zone
The stated tolerance zone remains the same at every actual feature size.
Inspection Method
Measure the geometric error directly and compare it to the stated tolerance value.
Do not add bonus tolerance from actual feature size when no material modifier is present.
Worked Check: Perpendicular Hole
A hole has perpendicularity diameter 0.10 to datum A with no material modifier. Its size is larger than nominal and axis error is 0.11 mm.
Modifier
None
RFS is implied by default.
Available
0.10 mm
Actual size does not add bonus tolerance.
Compare
0.11 > 0.10
The axis error exceeds the fixed zone.
The hole fails the RFS perpendicularity requirement.
Comparison Table
| Modifier | Bonus? | Best For |
|---|---|---|
| RFS | No | Constant control |
| MMC | Yes, away from most material | Assembly clearance |
| LMC | Yes, away from least material | Minimum stock or contact |
Notes
Many controls are always RFS because MMC and LMC are not applicable to them.
Older drawings may show an S modifier, but modern ASME practice treats RFS as implied.