PRIMARY REFERENCES
Measurement sources
Our data model prioritizes standards bodies and authoritative technical references.
BIPM and the SI Brochure
The International Bureau of Weights and Measures maintains the International System of Units and the authoritative SI Brochure.
NIST
The US National Institute of Standards and Technology publishes metric guidance, conversion relationships and technical measurement references.
Exact definitions
International agreements define relationships such as one inch equaling exactly 25.4 millimeters and one pound equaling exactly 0.45359237 kilogram. Convertora preserves those exact values.
Sources are selected for authority, relevance and traceability. Secondary sources may support explanatory context but do not override recognized standards.