GD&T Reference Tools

GD&T tools for drawing review intuition

Reference calculators for engineers who need to explain tolerance zones more clearly during reviews, supplier conversations, and markup discussions.

These tools are for reference only and are not exactly correct. They are approximation and explanation aids, not released drawing authority.

Reference approximation

GD&T Plus-Minus Tolerance Approximation Converter

Convert common GD&T tolerance zones into rough plus-minus values for intuition, including position, MMC/LMC bonus examples, profile, perpendicularity, parallelism, and flatness.

Explicitly reference-only: this is not an exact or standards-compliant conversion. Use it to make tolerance zones easier to understand during review discussions.

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