Each number in the chart indicates the oil’s performance under specific temperature ranges, helping vehicle owners choose the ideal option based on their environment and engine design.

Castrol's oil viscosity chart makes it easy to understand oil weight, thickness and grades. Understand how viscosity affects your engine's performance.

Oil viscosity refers to how thick or thin the oil is and how well it flows at different temperatures. This is represented by the numbers you see on oil bottles, such as 5W30 or 10W30, and it’s …

Find viscosity tables and charts for engine oil at multiple temperatures (viscosity and density values with their source).

To make it easier to understand, we’ve put together this oil viscosity chart, covering the viscosity scale of some of the most common engine oil specifications.

Use our oil viscosity comparison chart to identify and reference thickness at different temperatures for engines and machinery for ISO VG, AGMA, SAE Auto, and SAE Gear lubricants.

Free resource for comparing, choosing, and substituting oil for your machine using the Oil Viscosity Chart and our Big List of Oils. Learn the basics of oil, grease, and other lubricants for …

Sep 25, 2025 · In this guide, we’ll unravel the mysteries behind oil viscosity ratings and help you understand what they mean for your vehicle’s performance. Whether you’re a car enthusiast or …

Mar 23, 2011 · Many petroleum products are graded according to the ISO Viscosity Classification System, approved by the international standards organization (ISO). Each ISO viscosity grade …

Apr 10, 2024 · Dive into the world of oil viscosity ratings with an insightful Oil Viscosity Chart. This tool simplifies choosing the right oil grade for your vehicle, based on its resistance to flow at …