GD&T Check

GD&T Check helps mechanical engineering students validate their Geometric Dimensioning and Tolerancing callouts before submitting CAD drawings. Select a feature type, pick a GD&T symbol, enter your tolerance and datum references, and the app instantly tells you if your callout is valid or invalid — with a specific explanation of what it means and what to fix. CALLOUT CHECKER Build a feature control frame step by step. The app validates your combination against ASME Y14.5-2018 rules and flags errors like missing datum references, incompatible feature types, or incorrect material condition modifiers. PLAIN-ENGLISH EXPLANATIONS Every callout gets translated into a clear sentence explaining what it physically means — no more guessing what a tolerance zone actually controls. SYMBOL REFERENCE LIBRARY Browse all 14 GD&T symbols with definitions, when to use each one, common mistakes, and datum rules. Organized by category: Form, Orientation, Location, Profile, and Runout. SAVED HISTORY Keep a log of every callout you check. Useful as a running reference while working through drawings or homework. Built for students learning GD&T in college-level CAD, manufacturing, and metrology courses. Works fully offline — no account required, no internet needed.