Viscosity-Temperature Calculator
Based on the Walther equation: given the kinematic viscosities V1 and V2 of a lubricant at temperatures T1 and T2, calculate the viscosity V3 at any target temperature T3 (unit: mm²/s, i.e., cSt).
Instructions: ① Enter two temperature-viscosity reference points (higher temperature should correspond to lower viscosity); ② Enter the target temperature T3; ③ Click [Calculate] to obtain the corresponding viscosity.
cSt
cSt
Viscosity Index VI Calculator
Calculate Viscosity Index VI from kinematic viscosity at 40°C and 100°C using the piecewise formula per ASTM D2270, or solve for unknown viscosity at a specified VI in reverse.
Forward calculation: known viscosity at 40°C / 100°C → find VI
cSt
cSt
Reverse calculation 1: known VI and viscosity at 40°C → back-calculate viscosity at 100°C
cSt
Reverse calculation 2: known VI and viscosity at 100°C → back-calculate viscosity at 40°C
Note: When VI ≥ 100, use ASTM D2270 Formula B for extrapolation; accuracy depends on the value range, results are rounded to 2 decimal places.
cSt
Blending Viscosity Calculator
Supports viscosity prediction for blends of two base oils by ratio, as well as back-calculating the blend ratio for a target viscosity; temperature coefficient K automatically adapts to 100°C / 40°C / -5°C conditions.
A Known Ratio → Calculate Mixed Viscosity
cSt
cSt
%
B Known Target Viscosity → Calculate Mixing Ratio
cSt
cSt
cSt