GD&T True Position Calculator (MMC, LMC, RFS)
Instantly check position tolerance, bonus tolerance, and pass/fail
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What This GD&T True Position Calculator Does
This GD&T True Position Calculator helps you quickly determine whether a feature is within tolerance.
It automatically calculates:
• Radial deviation from the nominal position
• True position (diametrical value)
• Bonus tolerance for MMC and LMC conditions
• Total allowed tolerance
• Pass or fail result
This tool is designed for machinists, inspectors, and engineers who need fast, accurate answers without manual calculations.
How to Use This Tool
Enter the nominal (basic) position from the drawing
Enter the actual measured position
Input the position tolerance
Select feature type (hole or pin)
Select material condition (MMC, LMC, or RFS)
Enter feature size if applicable
Click Calculate
The results will instantly show true position, bonus tolerance, and pass/fail status.
Understanding Bonus Tolerance (MMC / LMC / RFS)
Bonus tolerance is additional tolerance gained when a feature departs from its maximum material condition.
• For holes: larger hole size = more bonus tolerance
• For pins: smaller pin size = more bonus tolerance
• MMC (Maximum Material Condition):
Bonus increases as material is removed
• LMC (Least Material Condition):
Bonus increases as material is added
• RFS (Regardless of Feature Size):
No bonus tolerance is applied
This calculator automatically applies the correct bonus tolerance based on your inputs.
Example
Basic position: (2.000, 1.500)
Actual position: (2.006, 1.496)
Tolerance: Ø0.010
Result:
True Position = Ø0.0144
Bonus = Ø0.0060
Total Allowed = Ø0.0160
Status = PASS
Related Machining Calculators
Use these related machining calculators to improve accuracy and save time:
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