Motor oil viscosity chart
SAE J300 grades
A motor oil viscosity chart shows how each SAE grade flows when cold (the W winter number) and how it protects when hot (the second number). Lower W numbers start better in the cold; higher second numbers are thicker at operating temperature. Use the grade your owner’s manual specifies.
Swipe or scroll sideways to inspect the full chart on small screens.
| Grade | Cold start (W) | Hot film (2nd number) | W | Hot |
|---|---|---|---|---|
| 0W-8 | Excellent (extreme cold) | Very thin (ultra-economy) | 0W | 8 |
| 0W-16 | Excellent (extreme cold) | Very thin (ultra-economy) | 0W | 16 |
| 0W-20 | Excellent (extreme cold) | Thin (economy) | 0W | 20 |
| 0W-30 | Excellent (extreme cold) | Medium | 0W | 30 |
| 0W-40 | Excellent (extreme cold) | Thicker | 0W | 40 |
| 5W-20 | Very good | Thin (economy) | 5W | 20 |
| 5W-30 | Very good | Medium | 5W | 30 |
| 5W-40 | Very good | Thicker | 5W | 40 |
| 5W-50 | Very good | Heavy (high-temp/load) | 5W | 50 |
| 10W-30 | Good (milder winters) | Medium | 10W | 30 |
| 10W-40 | Good (milder winters) | Thicker | 10W | 40 |
| 15W-40 | Limited in deep cold | Thicker | 15W | 40 |
| 20W-50 | Limited in deep cold | Heavy (high-temp/load) | 20W | 50 |
See it on a temperature scale
Drag to compare cold-start and operating-temperature behavior for 0W-20.
At 20 °C the engine is near ambient — the 0W winter rating governs how quickly 0W-20 reaches moving parts on start-up.
Frequently asked questions
What does the W in an oil grade mean?
W stands for winter. It rates cold-start flow — a lower W number flows more easily at low temperatures.
Is a higher second number better?
Not better — just thicker when hot. The right second number is the one your engine was designed for, listed in your manual.