LUBRICATION GUIDE
ISO VG Viscosity Grade Chart (ISO 3448)
By the PCG Technical Desk · Updated 27 September 2026
Quick answer: The ISO VG number is the oil's mid-point kinematic viscosity at 40 °C in cSt (mm²/s). Each grade allows ±10% around that mid-point. So an ISO VG 68 oil must measure between 61.2 and 74.8 cSt at 40 °C.
ISO 3448 viscosity grades
| Grade | Mid-point (cSt @ 40 °C) | Limits (cSt @ 40 °C) |
|---|---|---|
| ISO VG 2 | 2 | 1.98 – 2.42 |
| ISO VG 3 | 3 | 2.88 – 3.52 |
| ISO VG 5 | 5 | 4.14 – 5.06 |
| ISO VG 7 | 7 | 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 |
How to use the chart
- Hydraulic oils: commonly VG 32, 46, 68 (for example Servosystem 68).
- Industrial gear oils: commonly VG 150–460 (for example Servomesh SP 220).
- Turbine oils: VG 32–68 (Servoprime 32).
- Spindle oils: VG 2–22.
Manufacturers often publish tighter limits than ISO 3448. For example, IndianOil specifies 62–74 cSt for Servosystem 68. Always compare products using the viscosity at 40 °C, and note the viscosity index if the operating temperature varies widely.
ISO VG vs SAE grades
SAE engine-oil and gear-oil grades (15W-40, 85W-140) are measured differently (at 100 °C and at low temperature). They don't convert one-to-one to ISO VG, so don't substitute across systems without checking the actual viscosity data.
Outside Karnataka? The technical information on this page applies anywhere in India. PCG Business Solutions supplies SERVO in seven Karnataka districts. If you are in another state, send us your requirement and we will point you to IndianOil's authorised channel for your area, or answer any technical question about the grade.
Recommended SERVO grades
FAQ
FAQs
An oil whose kinematic viscosity at 40 °C is 68 cSt ±10%, i.e. between 61.2 and 74.8 cSt.
