Founder of TriboNet, Editor, PhD (Tribology), Tribology Scientist at ASML, The Netherlands. Expertise in lubrication, friction, wear and contact mechanics with emphasis on modeling. Creator of Tribology Simulator.
Viscosity Index Calculator (ISO 2909 / ASTM D2270)
On this page you will find several calculators to calculate viscosity index or viscosity depending on the temperature. You can also find a tool to interpolate the viscosity of lubricants based on the given viscosities at 2 temperatures. Read more about viscosity index here.
Here is a simple VI calculator to calculate viscosity index from the temperatures at 40°C and 100°C:
This calculator allows calculating kinematic viscosity at 100°C from the known VI and kinematic viscosity of the oil at 40°C:
This calculator allows calculating kinematic viscosity at 40°C from the known VI and kinematic viscosity of the oil at 100°C:
The common equation used to calculate the viscosity by interpolation between two reference points is with the Ubbelohde-Walther equation, which is adopted in ASTM D341. Here is a simple calculator to interpolate viscosity:
