Does every positive viscosity belong to an ISO VG band?

No. The bands have gaps. A value outside every listed interval must not be assigned to the nearest grade as if it conformed.

Is the number always the exact midpoint?

No. The exact midpoints for VG 2, 3, 5 and 7 are 2.2, 3.2, 4.6 and 6.8 mm²/s respectively.

Does ISO VG select a lubricant for my machine?

No. It classifies kinematic viscosity at 40 °C; it does not establish performance, chemistry, operating-temperature suitability or OEM approval.

Is cSt the same as mm²/s?

Yes. One centistoke equals one square millimetre per second.

Classification-band worksheet

ISO VG Band Lookup at 40 °C

Compare a documented kinematic-viscosity result with the ISO VG intervals. Values in the gaps are reported as no band match—not forced into a nearest grade.

20 designationsmm²/s = cStNo lubricant selection

Band comparison

Resultado

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Table midpoint at 40 °C

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Table interval at 40 °C

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ISO VG alone does not select or approve a lubricant.

Band rule

lower limit = 0.90 × table midpoint; upper limit = 1.10 × table midpoint

The grade designation is a rounded label. In particular,the table midpoints for VG 2,3,5 and7 are 2.2,3.2,4.6 and6.8 mm²/s—not2,3,5 and7.

The intervals have gaps. This worksheet uses inclusive displayed limits and returns no match outside every row. A real conformity decision at a boundary must follow the controlling measurement uncertainty and decision rule.

Designación	Midpoint (mm²/s)	Minimum (mm²/s)	Maximum (mm²/s)

Alcance

ISO 3448:1992,edition2,confirmed2023,establishes a viscosity classification for industrial liquid lubricants and related fluids. ISO3448:1992/Cor1:1993 is a published corrigendum. ISO VG is not an application,performance,chemistry,quality,temperature-range or interchangeability approval.

ISO 3104:2023,edition4,is a current procedure for kinematic-viscosity determination within its scope;this browser worksheet does not perform that laboratory measurement.

Evidence boundary: the ISO status/scope and corrigendum are official. Rows through VG1500 are publicly reproduced in Shell’s manufacturer pocketbook;Klüber publicly states the system spans VG2–VG3200 with ±10% tolerance. Exact licensed clause/table and corrigendum text remain NEEDS_LICENSED_SOURCE.

Fuentes

ISO3448:1992 official record; ISO3448:1992/Cor1:1993 official record; ISO3104:2023 official record; Shell Marine Lubricants Pocketbook; Klüber ISO VG overview.