هناك 7 وحدات أساسية في النظام الدولي للوحدات هي:== قائمة السوابق في النظام الدولي للوحدات (SI Prefixes) ==* نظم القياس* نظام سنتي جرام ثانية;Official* BIPM Bureau International des Poids et Mesures (SI maintenance agency) (home page)** BIPM brochure (SI reference)* ISO 80000-1:2009 "Quantities and units – Part 1: General"* NIST Official Publications** NIST Special Publication 330, 2008 Edition: The International System of Units (SI)** NIST Special Publication 811, 2008 Edition: Guide for the Use of the International System of Units** NIST Special Pub 814: Interpretation of the SI for the United States and Federal Government Metric Conversion Policy* Rules for SAE Use of SI (Metric) Units* EngNet Metric Conversion Chart Online Categorised Metric Conversion Calculator* U.S.
==External links==;Official* BIPM Bureau International des Poids et Mesures (SI maintenance agency) (home page)** BIPM brochure (SI reference)* ISO 80000-1:2009 "Quantities and units – Part 1: General"* NIST Official Publications** NIST Special Publication 330, 2008 Edition: The International System of Units (SI)** NIST Special Publication 811, 2008 Edition: Guide for the Use of the International System of Units** NIST Special Pub 814: Interpretation of the SI for the United States and Federal Government Metric Conversion Policy* Rules for SAE Use of SI (Metric) Units* EngNet Metric Conversion Chart Online Categorised Metric Conversion Calculator* U.S.