Enter a grade (ISO VG 68, SAE 15W-40, SAE 80W-90) or a measured kinematic viscosity with its temperature (68 cSt at 40 °C, 14 cSt at 100 °C). Below, an offered grade can be checked against the one wanted.
On the viscosity grade alone: the specification, the equipment maker’s approval and the type of oil are checked separately.
An industrial oil drum says ISO VG 68, an engine manual SAE 15W-40, a gearbox plate SAE 80W-90. Each is a viscosity grade: a range of kinematic viscosity in mm²/s (cSt) at a reference temperature, 40 °C for ISO VG and 100 °C for the SAE engine and gear grades. Enter a grade, or a measured viscosity with its temperature, and the converter gives the defining range, draws it beside its neighbours on a logarithmic scale, lists the grades of the other systems that overlap at the same temperature, checks an offered grade and writes an RFQ line.
Nothing here is converted between 40 °C and 100 °C: how far the viscosity of an oil falls between them depends on its viscosity index, which the grade does not give. Where charts pair grades across the two temperatures, the pair is shown as an approximate cross-reference, and only where two charts agree. A DIN 51502 code such as HLP 46 is decoded by the lubricant code reader, an ISO 4406 cleanliness code by the oil cleanliness code reader.
ISO 3448 gives 20 grades, ISO VG 2 to ISO VG 3200; the number is the midpoint of the kinematic viscosity at 40 °C in mm²/s, and the limits are 10 % either side. Older gearboxes may carry an AGMA number instead; the published AGMA to ISO VG charts differ, so AGMA numbers are not converted here: the gearbox maker’s manual gives the ISO VG grade.
SAE J300 grades engine oils and SAE J306 gear oils, both by the kinematic viscosity at 100 °C; the gear numbers are a separate scale with higher numbers. W grades are low-temperature grades; a multigrade oil such as 15W-40 or 80W-90 meets a W grade and a 100 °C grade together.
How far the viscosity of an oil falls from 40 °C to 100 °C depends on its viscosity index. Two ISO VG 100 oils with different viscosity indices can fall into different SAE grades, so the converter compares grades only at one reference temperature and gives the pairs across 40 °C and 100 °C only as an approximate cross-reference.
| ISO VG | Midpoint, mm²/s | Minimum | Maximum |
|---|---|---|---|
| ISO VG 2 | 2.2 | 1.98 | 2.42 |
| ISO VG 3 | 3.2 | 2.88 | 3.52 |
| ISO VG 5 | 4.6 | 4.14 | 5.06 |
| ISO VG 7 | 6.8 | 6.12 | 7.48 |
| ISO VG 10 | 10 | 9.00 | 11.0 |
| ISO VG 15 | 15 | 13.5 | 16.5 |
| ISO VG 22 | 22 | 19.8 | 24.2 |
| ISO VG 32 | 32 | 28.8 | 35.2 |
| ISO VG 46 | 46 | 41.4 | 50.6 |
| ISO VG 68 | 68 | 61.2 | 74.8 |
| ISO VG 100 | 100 | 90.0 | 110 |
| ISO VG 150 | 150 | 135 | 165 |
| ISO VG 220 | 220 | 198 | 242 |
| ISO VG 320 | 320 | 288 | 352 |
| ISO VG 460 | 460 | 414 | 506 |
| ISO VG 680 | 680 | 612 | 748 |
| ISO VG 1000 | 1000 | 900 | 1100 |
| ISO VG 1500 | 1500 | 1350 | 1650 |
| ISO VG 2200 | 2200 | 1980 | 2420 |
| ISO VG 3200 | 3200 | 2880 | 3520 |
| SAE grade | Minimum at 100 °C, mm²/s | Maximum at 100 °C, mm²/s |
|---|---|---|
| SAE 0W | 3.8 | — |
| SAE 5W | 3.8 | — |
| SAE 10W | 4.1 | — |
| SAE 15W | 5.6 | — |
| SAE 20W | 5.6 | — |
| SAE 25W | 9.3 | — |
| SAE 8 | 4.0 | < 6.1 |
| SAE 12 | 5.0 | < 7.1 |
| SAE 16 | 6.1 | < 8.2 |
| SAE 20 | not given | < 9.3 |
| SAE 30 | 9.3 | < 12.5 |
| SAE 40 | 12.5 | < 16.3 |
| SAE 50 | 16.3 | < 21.9 |
| SAE 60 | 21.9 | < 26.1 |
| SAE grade | Highest temperature for 150 000 mPa·s | Minimum at 100 °C, mm²/s | Maximum at 100 °C, mm²/s |
|---|---|---|---|
| SAE 70W | −55 °C | not given | — |
| SAE 75W | −40 °C | not given | — |
| SAE 80W | −26 °C | not given | — |
| SAE 85W | −12 °C | not given | — |
| SAE 65 | — | 3.8 | < 5.0 |
| SAE 70 | — | 5.0 | < 6.5 |
| SAE 75 | — | 6.5 | < 8.5 |
| SAE 80 | — | not given | < 11.0 |
| SAE 85 | — | 11.0 | < 13.5 |
| SAE 90 | — | 13.5 | < 18.5 |
| SAE 110 | — | 18.5 | < 24.0 |
| SAE 140 | — | 24.0 | < 32.5 |
| SAE 190 | — | 32.5 | < 41.0 |
| SAE 250 | — | 41.0 | — |
| ISO VG (40 °C) | SAE engine, approximate | SAE gear, approximate |
|---|---|---|
| ISO VG 32 | SAE 10W | — |
| ISO VG 46 | SAE 15W | SAE 75W |
| ISO VG 68 | SAE 20W | — |
| ISO VG 100 | SAE 30 | SAE 80W-90 |
| ISO VG 150 | SAE 40 | — |
| ISO VG 220 | SAE 50 | SAE 90 |
| ISO VG 320 | SAE 60 | SAE 140 |
The ISO VG and SAE limits are those of the standards as given by at least two independent sources for every figure; the cross-reference pairs are those two or more sources agree on. Left out, because the sources disagree: the lower limit of SAE 20 engine oil and of SAE 80 gear oil (both changed between editions of the standards); the cold-cranking and pumping limits of the engine oil W grades and the minimum viscosity at 100 °C of the gear oil W grades (different editions give different figures); the cross-reference pairs that are not in at least two charts; the AGMA numbers altogether (one chart checked puts every AGMA number one ISO grade higher than the others do, so the ISO VG grade for an AGMA number comes from the gearbox maker’s manual). The cross-reference is approximate: only the viscosity index of the actual oil links a grade at 40 °C to a grade at 100 °C, and for engine oils the chart pairs single grades, not multigrades.
ISO 3448 limits from the viscosity tables of a viscometer maker, an engineering reference site, a lubrication reference and two lubricant suppliers; SAE J300 in its 1999, 2015 and 2021 editions as given by an encyclopedia, two engineering reference sites and a viscometer maker; SAE J306 in its February 2019 revision as given by two lubrication reference sites and in a lubricant maker’s technical bulletin; cross-reference charts from an engineering reference site and two suppliers. Every limit and pair on this page is in at least two of them.
It is the midpoint of the kinematic viscosity at 40 °C in mm²/s (cSt). ISO 3448 allows 10 % either side, so an ISO VG 68 oil measures between 61.2 and 74.8 mm²/s at 40 °C. The grades run from ISO VG 2 to ISO VG 3200; for the four lowest the number is rounded, and ISO VG 2 has a midpoint of 2.2 mm²/s.
Not exactly. ISO VG is defined at 40 °C and the SAE engine and gear grades at 100 °C, and how far the viscosity of an oil falls between the two temperatures depends on its viscosity index. Two oils of the same ISO VG can fall into different SAE grades. Charts that pair them, such as ISO VG 100 with SAE 30, are approximate; this converter shows only the pairs two such charts agree on and computes no conversion.
They are separate scales. SAE J300 grades engine oils and SAE J306 grades gear oils, both by the kinematic viscosity at 100 °C: SAE 40 is 12.5 to below 16.3 mm²/s and SAE 90 is 13.5 to below 18.5 mm²/s, so the two ranges share 13.5 to 16.3 mm²/s. The gear number is higher only because the scale is different, and the oils are not interchangeable: their additives differ.
It is a multigrade engine oil that meets two SAE J300 grades at once: the low-temperature grade 15W and the 100 °C grade SAE 40, 12.5 to below 16.3 mm²/s. The W grades are set by cold-cranking and pumping tests; the sources checked give those limits from different editions of the standard, so this converter names the W grade and gives only its minimum viscosity at 100 °C, 5.6 mm²/s for 15W.
The viscosity grade, the specification or approval the equipment maker requires, the application (hydraulic, gear, turbine or crankcase), the quantity in litres and the packaging. A viscosity grade alone does not define the oil: two ISO VG 46 oils can be a hydraulic oil and a turbine oil with different additives.
A viscosity grade is a range of viscosity, not an oil. Add the specification or approval the equipment maker requires and a photograph of the drum label or the manual page, and Vessel Core checks them before an offer goes back.
