ISO 20457 Tolerance Table PDF: What You Actually Need to Know
Let’s break down what ISO 20457 really is, and where to get the correct tolerance information for your drawings.
Recommended Access
ISO 20457 does not cover geometric tolerances (flatness, roundness, etc.) – refer to ISO 20457-2 or GPS standards for those.
The standard is not a replacement for part-specific tolerance analysis – critical features may require tighter control.
Always obtain the official PDF from ISO or your national standards body (e.g., ANSI, BSI, DIN) for exact tables.
For engineers needing quick note blocks or Excel templates for CTQ (Critical to Quality) features, Super Ingenuity provides downloadable quality templates. OKW Gehäusesysteme Common Applications Primary Interest Part Designers iso 20457 tolerance table pdf
ISO 20457 provides:
PT grades
The standard uses a system of (Plastics Tolerances), similar to the IT grades in ISO 286. However, PT grades are generally wider than metal IT grades for the same nominal size. ISO 20457 Tolerance Table PDF: What You Actually
ISO 2768 (General Tolerances): This is the predecessor and more common standard. ISO 20457 is meant to eventually replace ISO 2768-1 and -2. However, many industries still use ISO 2768. The key difference is that ISO 20457 introduces the Fine/Medium/Coarse logic more clearly than the old f/m/c/v classes.
ISO 286 (Limits and Fits): ISO 286 is for specific fits (H7/g6, etc.). ISO 20457 is for general dimensions without specific fit requirements.
ASME Y14.5 (GD&T): ASME is the American standard. ISO 20457 is the European/International equivalent. Never mix them on the same drawing.