About The GD&T Positional Tolerance Calculator

The GD&T Positional Tolerance Calculator applies MMC bonus tolerance logic for a hole or shaft and reports total positional tolerance plus virtual condition size.

How to Use the GD&T Positional Tolerance Calculator Online

1. Select whether the feature is a hole or shaft.
2. Enter positional tolerance at MMC, MMC size, and actual size.
3. Run the calculator to review bonus tolerance, total positional tolerance, and virtual condition.

Choosing Options Correctly

Use drawing-defined MMC and actual measured size. This helper covers the basic bonus-tolerance relationship and does not replace full ASME/ISO GD&T interpretation, datum simulation, inspection strategy, or functional gage design.

Common Use Cases

• Check bonus tolerance for a measured hole or shaft.
• Explain MMC effects during drawing review.
• Estimate virtual condition for a simple feature.

Quick FAQ

Does this evaluate actual position error?
It helps calculate positional tolerance concepts; inspection still requires measured feature locations against the specified datum reference frame.

Does hole and shaft bonus work differently?
Yes. Bonus tolerance depends on the material condition modifier and whether the feature is internal or external.

What is the common GD&T mistake here?
Using the wrong MMC/LMC direction or ignoring the datum reference frame can make the bonus tolerance meaningless.

Can I use this for production acceptance?
Use it as a check aid, then verify against the drawing, ASME/ISO GD&T rules, gauge strategy, and inspection method.