DIN EN ISO 5459:2025-12

Clearly define datums and datum systems in geometrical product specifications

DIN EN ISO 5459 specifies the rules for datums and datum systems in geometrical product specification (GPS). It describes the terminology, methodology and graphical representation of datums used to establish the location, direction and orientation of geometrical tolerances. The standard helps design engineers, quality specialists and metrology professionals define geometrical requirements unambiguously and avoid misunderstandings between design, manufacturing and inspection.

What is DIN EN ISO 5459 about?

The standard defines the rules for the establishment, indication and interpretation of datums and datum systems within the GPS system. It focuses on datum features, datum targets, single datums, common datums and datum systems, as well as their use in technical drawings and digital product models. It also describes methods for associating real geometrical features with ideal datum features, constraining degrees of freedom and specifying geometrical requirements unambiguously.

New provisions include rules for datum coordinate systems, extended specification operators, new modifiers, and the filtration and association of datum features. The standard therefore reflects the growing importance of digital product models and modern inspection methods.

Topics covered

• Geometrical product specification (GPS) and geometrical tolerancing
• Datum features, datum targets and datum systems
• Single datums and common datums
• Datum coordinate systems and their indication
• Situation features and invariance classes
• Association methods for datums
• Specification operators, modifiers and default rules
• Filtration of datum features and datum planes
• Graphical representation in technical drawings and 3D models

Practical relevance

Datums form the basis for the unambiguous definition of geometrical tolerances and play a central role in the manufacture and inspection of precision components. DIN EN ISO 5459 helps companies define datum systems consistently and communicate geometrical requirements clearly. This reduces scope for interpretation and improves the comparability of measurement results.

The standard is particularly relevant for companies that need to define and inspect geometrical tolerances unambiguously. It supports the consistent application of modern GPS standards and improves the comparability of measurement results throughout the entire process chain, from design and manufacturing to quality assurance.

Changes compared with DIN EN ISO 5459:2013-05

The 2025 edition has been comprehensively revised and expanded. The most important changes include:

• Introduction of the terms datum coordinate system, datum coordinate system indicator and datum coordinate system identifier
• Expanded graphical symbols and modifiers for datum features and datum targets
• New rules for the indirect indication of datum target areas and the indication of situation features
• New section on specification operators for datums
• New annexes on datum coordinate systems, filtration and GPS relationships
• Updated association methods and default rules for datum systems
• Editorial and technical revision of the document

Target group

• Design engineers and development engineers
• Technical drafters and CAD users
• Quality managers
• Inspection and metrology professionals
• Manufacturing engineers
• Mechanical engineering companies
• Manufacturers of measurement systems
• Specialists in geometrical product specification (GPS)

Conclusion

DIN EN ISO 5459 provides the central basis for the unambiguous definition and application of datums within geometrical product specification. It supports consistent geometrical communication between design, manufacturing and metrology and contributes to the reliable application of modern GPS standards.

This document replaces DIN EN ISO 5459:2013-05 .