Engine Oil Viscosity Chart

How to use this engine oil viscosity chart

1. Set your coldest start. Drag the slider to the overnight low where you actually park. Not the daytime high, and not the record low from 1983 — the temperature the engine will be sitting at when you turn the key in February.
2. Pick the grade your manual calls for. It's printed on the oil-fill cap on most engines built since about 2005.
3. Read the bars. Each SAE winter grade is drawn from the coldest temperature it's tested to pump at, rightwards. Where the red marker crosses a green bar, that grade passed both of its cold tests at your temperature. Amber means it pumps but you're past the cranking test. Hatched means it isn't tested that cold at all.
4. Compare two grades. The second tab puts any two labels side by side and tells you what actually changes between them — which is usually less than the internet claims.
5. Have a data sheet? The third tab takes the two kinematic viscosities every oil publishes (at 40 °C and 100 °C) and plots the whole curve, so you can read the viscosity at any temperature in between.
6. Save it. "PDF chart" downloads the complete J300 table plus your lookup. "Share" copies a link with your settings baked in.

Why this chart is different from other oil viscosity chart pages

Search this term and the first thing Google shows you is an image pack, which tells you exactly what people want: a chart they can look at. Then the organic results start, and almost none of them have one. The page ranking at the top is titled "Oil Viscosity Chart" and contains five paragraphs of prose and no chart of any kind. Here's what we built instead:

• An interactive chart, not a JPEG. Every temperature-band graphic on this search is a static image, usually made by an oil brand, often for a market that isn't the US. Ours moves, in your units, against your temperature.
• The current standard. One of the few pages on page one that prints real numbers is running the pre-1999 classification — borderline pumping temperatures and cold-cranking limits of 3,250 cP that J300 hasn't used in a quarter century. Every figure here is from J300_202104.
• The grades nobody else lists. SAE 16 was added in 2013, SAE 8 and 12 in 2015. If you own a recent Toyota hybrid running 0W-16, most charts on this search act like your oil doesn't exist.
• Fahrenheit as a first-class unit. The standard is written in Celsius. You buy oil in a country that isn't. Every temperature on this page flips.
• The comparison answers, with numbers. "Which is thicker, 10W-30 or 5W-30?" is one of the questions Google itself surfaces on this search. Nothing on page one answers it with a figure. The compare tab does, in both directions.
• Free to embed. No competitor on this search offers an embed. Forums, club sites, and shop blogs can drop this chart in with one line of HTML.

How it works — what the two numbers actually guarantee

An oil label like 5W-30 is not one measurement, it's two, taken at opposite ends of the thermometer, and they're assigned in completely different ways.

The W number is a temperature, not a thickness

The winter half is assigned by two cold tests. The cold-cranking simulator (ASTM D5293) measures how hard the oil is to shear at starter speed; the mini-rotary viscometer (ASTM D4684) measures whether the pump can move it at all. Each W grade has a temperature attached to each test, and an oil gets the grade for the coldest temperature at which it passes. A 5W oil is one that stays under 6,600 cP at −30 °C on the cranking test and under 60,000 cP at −35 °C on the pumping test.

That's why this chart draws the bars where it does. The pumping temperature is the honest floor: below it, nobody has tested that the oil reaches the bearings. It is not a cliff — an oil doesn't turn to tar one degree past its rating — but it's the last temperature anyone measured, and treating it as the limit is the conservative reading.

The second number is a viscosity band, and it isn't a climate decision

The non-winter half is a kinematic viscosity range at 100 °C, measured by ASTM D445 or D7042, plus a minimum high-temperature high-shear viscosity at 150 °C. An SAE 30 oil lands between 9.3 and 12.5 cSt at 100 °C with an HTHS floor of 2.9 cP. That band describes the film your engine's bearing clearances were designed around.

Older charts — the ones filling that image pack — show a hot-weather axis suggesting you move up a grade in summer. That advice is a leftover. Because EPA fuel-economy testing requires a manufacturer to recommend the same grade it certified the engine with, modern manuals specify one grade year-round and the climate-range charts were retired along with the practice. The second number belongs to the engine. Only the W number is yours to argue about, and only within what your manual allows.

The curve between the two anchor points

The third tab uses the Walther equation from ASTM D341, which says that for a petroleum oil, log₁₀(log₁₀(ν + 0.7)) = A − B·log₁₀(T), with viscosity in centistokes and temperature in kelvin. Two known points fix A and B, and every other temperature falls out. Feed it the 40 °C and 100 °C figures from your oil's data sheet and you get the whole curve.

How accurate is it? We checked, and we'll show you where it fails. Against six oils that Anton Paar measured on a lab viscometer, fitting at 40 °C and 100 °C and predicting every temperature in between, the worst error was 2.7% and four of the six stayed under 1.4%. Extrapolate down to 0 °C, though, and the error grows to as much as 10.6%. That's not a bug in the arithmetic — it's viscosity-index improvers doing their job. A multigrade oil is deliberately engineered to stop following the straight line the equation assumes. The tool says which side of the anchors you're on and quotes the matching error band.

Worked examples

A 5W-30 Civic in Minneapolis. A −25 °F morning is a real January in Minnesota. Put that in and 5W-30 comes back amber: −25 °F is about −32 °C, still inside 5W's pumping test at −35 °C but below the −30 °C its cranking test is run at. The oil gets to the bearings. What you'll actually notice is the starter groaning, because a lead-acid battery has lost roughly a third of its cranking amps by then. The fix that helps most at that temperature isn't thinner oil, it's a battery that still holds a charge. Nudge the slider up to −20 °F and the same oil goes green, which is how narrow that window is.

The same Civic in Fairbanks. At −40 °F — which is also −40 °C, the one place the scales meet — 5W-30 goes red. Its pumping test is run at −35 °C, so you're five degrees below the coldest temperature anyone measured it at. The tool's suggestion is 0W-30: same hot band, same HTHS floor, same everything your engine cares about once it's warm, but tested to pump five degrees colder. That's the whole point of the keep-the-second-number rule, and it's what the cold-climate note in most owner's manuals says too.

"Can I put 10W-30 in instead of 5W-30?" Open the compare tab. Hot side: identical. Both are SAE 30, both must land between 9.3 and 12.5 cSt at 100 °C, both carry a 2.9 cP HTHS minimum. Once the engine is warm there is no difference the standard recognises. Cold side: 5W is tested to pump at −35 °C, 10W at −30 °C, so you give up five degrees of the only thing that separates them. In Phoenix that costs you nothing. In Denver in January it's the whole reason your manual says 5W.

Frequently asked questions

Which oil is thicker, 10W-30 or 5W-30?

At operating temperature, neither — they're the same grade. Both have to land in the SAE 30 band, 9.3 to 12.5 cSt at 100 °C, with the same 2.9 cP high-shear minimum. The difference is entirely cold: 5W-30 is tested to pump down to −35 °C and 10W-30 only to −30 °C, so 5W-30 is the thinner of the two on a winter morning and indistinguishable from it on a summer afternoon. This is the single most common misreading of the label — people treat the first number as a thickness when it's a temperature rating.

What engine oil viscosity should I use?

The one in your owner's manual or on the oil-fill cap, without improvising on the second number. Modern engines are designed around a specific film thickness at operating temperature, and the manufacturer certified its fuel economy numbers on that grade. Where you have room to move is the winter number, and only if the manual lists an alternative — most do, in a cold-climate footnote that reads something like "0W-20 may be used below −20 °F." Set your coldest morning in the chart above to see whether your specified grade still covers it.

What happens if I put 10W-30 instead of 5W-30?

In a warm climate, functionally nothing. In a cold one you've narrowed your cold-start margin by five degrees, and the risk is the few seconds after a very cold start when the pump is pulling against oil it can't move fast enough. That's when bearing and camshaft wear actually happens — not at highway speed. You may also void a warranty claim if the engine is under one and the manual is specific. If it's what you've got and it's 40 °F out, run it and buy the right grade next time.

Is higher or lower number oil thicker?

Higher is thicker, but only within the same half of the label. A 40 is thicker than a 30 at operating temperature. A 10W is thicker than a 5W at cold-start temperature. Comparing across halves is meaningless — a 20W-50 and a 0W-20 don't sit in any single order, they cross over as the engine warms up. That's exactly what the curve on the third tab is showing you.

Is there an engine oil viscosity chart PDF I can print?

Yes — the "PDF chart" button on the tool generates one on your device, with the full SAE J300 winter and non-winter tables, every temperature in both °C and °F, and whatever lookup you had on screen. No email, no signup, nothing uploaded anywhere. It's sized for a US Letter page and prints legibly in black and white, which is what a shop wall actually needs.

Related tools

• Spark Plug Gap Chart by Vehicle — the same searchable-spec treatment for plug gaps, with a re-gap verdict per engine.
• Per-Vehicle Maintenance Schedules — what's due at your mileage, including the 0W-16 catch on recent Toyotas.
• Ft-Lbs to Nm Torque Converter — for the drain plug you're about to overtighten.
• Metric Bolt Torque Chart — M6–M24 across Class 8.8 / 10.9 / 12.9, live for dry, oiled, and anti-seize.
• Browse all free tools by Mike Reeves →

Mike's recommendations for an oil change

Reading the chart is the easy part. The bottle you put in and the filter you screw on are what the engine actually lives with:

• Best Synthetic Motor Oil — if the chart pushed you toward a 0W or 5W, this is where you're shopping. Getting a base oil that still pumps at −35 °C is largely a synthetic problem; conventional stock rarely gets there without a lot of chemistry.
• Best High-Mileage Motor Oil — past about 75,000 miles, seal conditioners and a slightly heavier film do more good than shaving another point off the viscosity.
• Best Oil Filters — cold thick oil is exactly what forces a filter's bypass valve open, and a weak anti-drainback valve is why some engines rattle for two seconds on startup.

Still deciding whether the upgrade is worth it? Synthetic vs conventional oil goes through where the money actually goes, Mobil 1 vs Castrol GTX compares the two bottles most people are choosing between, and our DIY oil change guide walks the job itself.

Sources & methodology

• SAE International — J300_202104, Engine Oil Viscosity Classification — the source of every limit on this page, winter and non-winter.
• ASTM D5293 — apparent viscosity by cold-cranking simulator, the test behind each W grade's cranking temperature.
• ASTM D4684 — low-temperature pumping viscosity by mini-rotary viscometer, the test behind the pumping floor this chart draws its bars from.
• ASTM D341 — viscosity-temperature charts for liquid petroleum products; the Walther equation used on the third tab.
• Anton Paar — Viscosity of Engine Oil — SVM-measured kinematic viscosities for six real oils from 0 °C to 100 °C, used to cross-validate the Walther implementation and to fill the reference presets.
• SAE press material on the SAE 16 (2013) and SAE 8 / 12 (2015) grade additions, and on the 2013 revision that raised the SAE 20 floor from 5.6 to 6.9 cSt.

Both J300 tables and every rule above are tested by fixtures.test.mjs alongside the component source — 834 assertions covering each grade's limits, the verdict banding at every boundary, the recommendation logic across the full temperature range, the Walther equation against six lab-measured oils, and table-wide invariants including the deliberate overlap between the SAE 8, 12, and 16 bands. About Mike Reeves · Last reviewed August 21, 2026.

Embed this chart on your site

Free for car and truck forums, marque clubs, restoration threads, fleet and vocational instructors, oil-change shops, and anyone who is tired of linking to a JPEG. Required attribution is included in the snippet — no fee, no signup, no analytics attached to the embed.

The default height fits the interactive lookup and both J300 reference tables with no internal scrollbar. If you only want the temperature lookup and the verdict, drop height to about 700 and the rest simply scrolls.

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  Engine oil viscosity chart by
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  &middot; Reviewed by Mike Reeves, ASE Master Technician
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