Viscosity Grade Chart — ISO VG Bands & SAE J300 Engine Oil Limits
ISO VG viscosity grades with computed min-max bands per ISO 3448, plus SAE J300 engine-oil kinematic viscosity limits at 100 C.
Updated August 22, 2026
Industrial lubricants are graded by one number: the ISO VG grade is the kinematic viscosity midpoint at 40 °C in centistokes, and ISO 3448 (ASTM D2422) defines each grade as a band of ±10% around that midpoint — so the min and max columns below are computed from the definition, not looked up. The ladder steps by roughly 1.5× per grade, which is why the familiar hydraulic and gear oil numbers run 22, 32, 46, 68, 100, 150. Only the four smallest grades have midpoints that differ from their names (VG 2 is centered on 2.2 cSt, VG 5 on 4.6), a quirk inherited from rounding the series to convenient labels.
Engine oils use a different system: SAE J300 grades are defined by kinematic viscosity at 100 °C — engine operating temperature — plus cold-cranking and pumping limits for the W grades and high-shear minimums that this chart leaves to the standard. A “30” oil must sit between 9.3 and 12.5 cSt at 100 °C; a “10W-30” must meet the 10W cold-side limits and the 30 hot-side band at once. The two scales measure at different temperatures, so a single conversion between ISO VG and SAE grades does not exist — see the FAQ before trusting any crosswalk chart.
ISO VG Grades — Kinematic Viscosity at 40 °C (ISO 3448 / ASTM D2422)
| ISO VG | Midpoint (cSt) | Min (cSt, computed −10%) | Max (cSt, computed +10%) |
|---|---|---|---|
| VG 2 | 2.20 | 1.98 | 2.42 |
| VG 3 | 3.20 | 2.88 | 3.52 |
| VG 5 | 4.60 | 4.14 | 5.06 |
| VG 7 | 6.80 | 6.12 | 7.48 |
| VG 10 | 10.0 | 9.00 | 11.0 |
| VG 15 | 15.0 | 13.5 | 16.5 |
| VG 22 | 22.0 | 19.8 | 24.2 |
| VG 32 | 32.0 | 28.8 | 35.2 |
| VG 46 | 46.0 | 41.4 | 50.6 |
| VG 68 | 68.0 | 61.2 | 74.8 |
| VG 100 | 100 | 90.0 | 110 |
| VG 150 | 150 | 135 | 165 |
| VG 220 | 220 | 198 | 242 |
| VG 320 | 320 | 288 | 352 |
| VG 460 | 460 | 414 | 506 |
| VG 680 | 680 | 612 | 748 |
| VG 1000 | 1000 | 900 | 1100 |
| VG 1500 | 1500 | 1350 | 1650 |
cSt = mm²/s at 40 °C. The band is ±10% of the midpoint by definition (ISO 3448), so the min/max columns are computed, not transcribed. Common shop mappings: VG 32/46/68 hydraulic oils, VG 100–320 gearbox oils, VG 220–460 worm drives.
SAE J300 Engine Oil Grades — Kinematic Viscosity at 100 °C
| SAE grade | KV100 min (cSt) | KV100 max (cSt) |
|---|---|---|
| 0W | 3.8 | — |
| 5W | 3.8 | — |
| 10W | 4.1 | — |
| 15W | 5.6 | — |
| 20W | 5.6 | — |
| 25W | 9.3 | — |
| 8 | 4.0 | < 6.1 |
| 12 | 5.0 | < 7.1 |
| 16 | 6.1 | < 8.2 |
| 20 | 6.9 | < 9.3 |
| 30 | 9.3 | < 12.5 |
| 40 | 12.5 | < 16.3 |
| 50 | 16.3 | < 21.9 |
| 60 | 21.9 | < 26.1 |
SAE J300, April 2021 revision. W grades additionally carry cold-cranking (CCS) and pumping (MRV) limits at low temperature, and grades 8–60 carry high-temperature high-shear (HTHS) minimums — consult J300 for those columns. The SAE 20 minimum has been 6.9 cSt since the 2013 revision (previously 5.6).
Sources & Further Reading
- ISO 3448 / ASTM D2422 viscosity classification (±10% band definition), midpoints verified across two independent lubricant-industry reproductions (Cougar Lubricants ISO 3448 table, VG 2–1500; Engineers Edge ISO 3448 grade table)
- SAE J300 (April 2021 revision) as reproduced by the Wikipedia J300 table and IPEC oil-viscosity-grading technical page; Ölezol J300 chart as third check — SAE 20 minimum 6.9 cSt per the 2013+ revisions (IPEC documents the change from 5.6)
Frequently Asked Questions
Is ISO VG 46 the same as SAE 15W-40 or SAE 20?
Neither, strictly. ISO VG is measured at 40 °C and SAE J300 at 100 °C, so any equivalence depends on the oil’s viscosity index — how steeply it thins with heat. A VG 46 mineral oil with VI ≈ 100 lands near the SAE 10W/20 region, but a high-VI synthetic VG 46 behaves differently at 100 °C. That is why published crosswalk charts disagree with each other and why this page does not print one: compare actual KV40 and KV100 numbers from the datasheets instead.
What do the min and max columns of the ISO table actually mean?
They are the pass band for labeling: an oil may be sold as ISO VG 68 only if its kinematic viscosity at 40 °C measures between 61.2 and 74.8 cSt — the midpoint ±10%, straight from the ISO 3448 definition. The bands do not overlap and do not touch: an oil measuring 55 cSt is neither a VG 46 nor a VG 68 and would be sold against a different specification.
Why does the ISO ladder step by about 1.5× each grade?
The grades follow a rounded Renard-series progression, so each grade is roughly 50% more viscous than the one below — VG 32 → 46 → 68 → 100. One step is a meaningful, noticeable change in film thickness and pumping loss, which keeps the list short: 18 grades cover everything from spindle oils near 2 cSt to open-gear compounds at 1,500 cSt. If a machine calls for something between grades, that is what the manufacturer’s KV40 spec (not the grade label) is for.
What does the W in 10W-30 mean, and why does the 30 have two numbers here?
W is winter: the 10W half is a set of cold-temperature limits (cranking viscosity at −25 °C, pumping at −30 °C, and a KV100 floor of 4.1 cSt), while the 30 half is the hot-side band in this chart — 9.3 to below 12.5 cSt at 100 °C. A multigrade must satisfy both at once. Two straight grades can even overlap on paper: SAE 8, 12, and 16 interleave, existing for modern low-viscosity fuel-economy oils.
Try the Calculators
Viscosity Grade Chart — ISO VG Bands & SAE J300 Engine Oil Limits — reuven.tools/reference/viscosity-grades — verified against: ISO 3448 / ASTM D2422 viscosity classification (±10% band definition), midpoints verified across two independent lubricant-industry reproductions (Cougar Lubricants ISO 3448 table, VG 2–1500; Engineers Edge ISO 3448 grade table); SAE J300 (April 2021 revision) as reproduced by the Wikipedia J300 table and IPEC oil-viscosity-grading technical page; Ölezol J300 chart as third check — SAE 20 minimum 6.9 cSt per the 2013+ revisions (IPEC documents the change from 5.6)