Viscosity index is a measure of a fluid's sensitivity to change in viscosity with change in temperature.
- Abbreviated as VI
- ASTM Standards
- ASTM D2116 - Standard Method for Conversion of Kinematic Viscosity to Saybolt Universal Viscosity or to Saybolt Furol Viscosity
- ASTM D2270 - Standard Practice for Calculating Viscosity Index from Kinematic Viscosity at 40 and 100°C
- ASTM STP168 - ASTM Viscosity Index Calculated from Kinematic Viscosity
- ASTM STP532 - Viscosity Testing of Asphalt and Experience with Viscosity Graded Specifications