Oil Basics · Reviewed Oct 3, 2026
How to Read an Oil Label: API SQ, SAE Grades and Approvals
A motor oil label packs a lot into a small space. Use this guide to decode the viscosity grade, the API symbols and the approvals, then match them to what your owner’s manual calls for.
By Alan Williams, independent AMSOIL Dealer since 2004, Tomball, TX
What do the numbers and symbols on a motor oil bottle mean?
The SAE grade (like 0W-20) is viscosity: the first number with “W” is cold-start flow, and the second is thickness at engine temperature. The API “donut” shows the service category, currently API SQ, and the starburst shows ILSAC GF-7 compliance.
Always match the viscosity and specifications in your owner’s manual.
SAE viscosity grade (for example 0W-20)
The number before the “W” (winter) shows how well the oil flows when cold, and a lower number flows more easily. The number after the dash shows thickness at operating temperature. Use the grade your manual specifies, and use the viscosity selector if you need help.
API donut and starburst
| Mark | What it shows | Status (Aug 2026) |
|---|---|---|
| API donut | Service category and viscosity grade | Current gasoline categories: SQ and SP |
| API SQ | Latest gasoline category since March 2025 | Backward compatible with SP and earlier |
| Starburst | ILSAC GF-7A compliant oil | Current |
| Shield | ILSAC GF-7B (0W-16 only) | Current |
| API CK-4 / FA-4 | Diesel service categories | For diesel engines |
API SP and ILSAC GF-6 oils are still sold during a transition period. If your manual calls for SP, an SQ oil of the right viscosity is the current replacement.
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OEM approvals
Many automakers add their own approvals, such as GM dexos, Ford WSS, and European codes like VW or BMW. If your manual lists one, the bottle’s label or data sheet must list it too. An API mark alone does not guarantee an OEM approval.
Other label details
- Full synthetic, blend or conventional: see our synthetic oil guide and synthetic vs conventional comparison.
- High mileage: oils with seal conditioners for older engines.
- Quantity and capacity: check how much oil your engine takes.
Oil label FAQ
What does 0W-20 mean?
A multigrade oil that flows like a 0-weight oil when cold and has the thickness of a 20-weight oil at operating temperature.
What is API SQ?
The latest API gasoline engine oil category, first licensed in March 2025, and backward compatible with SP and earlier.
Is API SP still current?
SP is still on shelves, but SQ is the newest category. Use what your manual specifies.
What is the API starburst?
It shows an oil that meets ILSAC GF-7A (or the GF-7B shield for 0W-16).
Can I use SQ oil where SP is recommended?
Yes. SQ is backward compatible with SP, if the viscosity is correct.
Pick the right oil, then pay less for it
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Sources (checked Oct 3, 2026): API engine oil service categories (OilSpecifications.org) · ILSAC specifications summary · Tomorrow’s Technician: API licenses GF-7 oils
AMSOIL is a registered trademark of AMSOIL INC. LubeOilSales.com is operated by Alan Williams, an independent AMSOIL Dealer (Dealer #1243776), and is not owned or endorsed by AMSOIL INC. If you join through my links, I may earn a commission at no extra cost to you. This guide is general information. Follow your owner’s manual and consult a qualified professional when in doubt. Content last reviewed October 3, 2026.