TaskJunction

GD&T Fit Calculator

MMC and LMC limits with min and max clearance for shaft-hole fits.

Inputs

Results

Hole MMC
—
Hole LMC
—
Shaft MMC
—
Shaft LMC
—
Min Clearance
—
Max Clearance
—
Fit Type
—

Formula

  • Hole MMC = smallest hole (nominal + lower deviation)
  • Hole LMC = largest hole (nominal + upper deviation)
  • Shaft MMC = largest shaft (nominal + upper deviation)
  • Min clearance = hole MMC − shaft MMC

About this calculator

Part of our GD&T & Metrology Calculators collection. True position, fits, ISO tolerances, and surface roughness.

How it works

MMC and LMC are the extreme sizes that control assembly conditions. Min clearance uses the smallest hole with the largest shaft. Max clearance uses the largest hole with the smallest shaft. Fit code classifies clearance, transition, or interference.

Enter your values in the inputs above and click CALCULATE. Results appear on the right without a page reload. No login and no server upload.

Worked example

25 mm hole 0/+0.021, shaft −0.033/−0.020.

  1. Hole MMC = 25.000, LMC = 25.021
  2. Shaft MMC = 24.980, LMC = 24.967
  3. Clearance 0.020 to 0.054 mm

Result: Clearance fit with 20 to 54 µm gap range.

When to use

  • Quick shaft-hole fit check from drawing deviations
  • Finding min/max assembly clearance at MMC/LMC
  • Classifying clearance, transition, or interference fit

Limitations

  • Manual deviation entry; not full ISO fit class lookup
  • Does not include form tolerance or runout effects
  • MMC/LMC labels follow size extremes, not GD&T datum rules alone

FAQ

What is MMC for a hole?
Maximum Material Condition for a hole is its smallest diameter — the condition with least material.
Min clearance vs max clearance?
Min clearance uses the tightest assembly (small hole, large shaft). Max clearance uses the loosest.

Privacy and accuracy

Every calculation runs locally in your browser. Your design data never leaves your device. Results are intended for preliminary engineering work. Always verify critical designs with qualified review and applicable standards before production use.

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