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Trying to figure out the difference between AMSOIL, Royal Purple and Mobil 1 synthetic oil brands?

The truth is, there is a bunch of bad information out there about finding the best brand of oil for your vehicle. That’s why we decided to write an article that would put everything we know about oil out into the open.

After spending dozens of hours researching these brands, we learned a few interesting facts to share with you.

First, let’s talk about the elephant in the room…

The Truth About AMSOIL

Why are people on the internet so passionate about AMSOIL?

The reason is simple: AMSOIL products are distributed by independent dealers approved by AMSOIL.

This is also known as a Multi-Level Marketing company or MLM. Other famous companies that operate using this model include Advocare, Amway, Avon, Herbalife, Mary Kay and many more.

But first, a little back story…

Back in 1972 AMSOIL produced the first API-qualified synthetic motor oil. However, at the time consumers had no desire for a more expensive synthetic engine oil, so AMSOIL devised a new marketing strategy.

They decided to create a “Dealer Network” of salesmen to help sell the product to their friends and family members.

In fact, it was this MLM strategy that helped AMSOIL grow into the brand it is today.

Starting in 1973 AMSOIL was sold exclusively by independent dealers that could help sell the benefits of using a synthetic oil. Not surprisingly, the new strategy worked.

So, how does the whole MLM thing work?

AMSOIL dealers pay a yearly membership fee to receive products at wholesale pricing then sell them to their customers at retail prices. This, of course, is how retail business models work.

However, what makes AMSOIL different is that the authorized dealers also receive a commission on the sales of other dealers below them in the pyramid.

That’s why AMSOIL dealers are not only are passionate about selling oil, but they want you to start selling AMSOIL as well.

So if you are searching for information about AMSOIL online and keep finding articles from AMSOIL dealers, this is why. They make money if they can convince you to buy their oil and become a dealer in the process.

In our research we found it difficult to have an honest conversation with AMSOIL dealers about the difference between AMSOIL, Royal Purple and Mobil 1 because they are financially biased. Since they make more money selling AMSOIL, it is a no-brainer that they would stand up for their brand whether it is superior or not.

Of course, just because AMSOIL is an MLM company does not mean that they sell bad oil. The purpose of this back story was to make sure we are all on the same page about reviews of AMSOIL you might read online.

What to Look For When Comparing AMSOIL, Royal Purple and Mobil 1

In our research of comparing Royal Purple, Mobil1 and AMSOIL, there are only a few important factors to consider. These include viscosity grade, oil change interval, and price.

What to look for when shopping for motor oil:

  • Viscosity Grade
  • Change Interval
  • Price

Viscosity Grade

Despite what most so-called experts like to claim, the only important factor to consider when picking an oil for your engine is the viscosity grade. In all honesty, the leading brands of synthetic oil on the market are practically identical.

So, the most important decision for the consumer to make is which viscosity grade is appropriate for their vehicle. The best place to find this information is your vehicle owner’s manual.

The most common engine oil grades include:

  • 0W-20
  • 0W-40
  • 5W-20
  • 5W-30
  • 5W-40
  • 10W-30
  • 10W-40
  • 15W-40
  • 20W-50

Using a synthetic engine oil with the wrong viscosity can cause premature engine wear, lower gas mileage and potential damage to your engine.

So before you head to the autoparts store to buy 5 quarts of oil, check your owner’s manual to see which viscosity your vehicle manufacturer recommends.

See also: 5W30 vs 10W30

Change Interval

The next factor to consider when comparing AMSOIL, Royal Purple and Mobil 1 is the change interval.

For the longest time, conventional motor oils needed to be changed every 3,000 miles or 6 months, whichever came first. Today, most car manufacturers recommend changing the engine oil every 5,000 or 7,500 miles.

However, synthetic oils have a much longer lifespan and can last up to one year without being changed.

If you don’t like changing your oil or forking paying $60 bucks every few months, a synthetic oil with a longer change interval may be a good fit for you.

Keep in mind the the recommended change interval varies depending on your driving habits. Most oil companies divide driving habits into two categories: normal service and severe service.

For instance, AMSOIL defines normal service as “personal vehicles frequently traveling greater than 10 miles at a time and not operating under severe service.”

And, they define severe service as “turbo/supercharged engines; commercial or fleet vehicles; excessive idling; daily short-trip driving less than 10 miles (16km); frequent towing, plowing or hauling; dusty-driving conditions.”

If your vehicle meets any of the severe service criteria, your vehicle may not qualify for the extended change interval. Instead you should change your oil more frequently to prevent possible damage to your engine.

So how do the change intervals of AMSOIL, Royal Purple and Mobil 1 compare?

Brand Normal Service Severe Service
AMSOIL Signature Series 25,000 miles / 1 Year 15,000 miles / 1 Year
Royal Purple Synthetic 12,000 miles / 1 Year 12,000 miles / 1 Year
Mobil 1 Extended Performance 15,000 miles / 1 Year See Owner’s Manual


The final factor to consider when comparing AMSOIL, Royal Purple, and Mobil 1 is the price per quart. Using synthetic is more expensive than conventional oil, however as we pointed out, the drain interval is much longer. Upgrading to synthetic can actually save you money depending on your driving style and drain interval.

The prices mentioned here were found online at the time the article was published. Current prices may differ. Keep in mind that prices at local auto parts are typically higher than those found online. It is also common for prices to differ depending on your location and current sales or promotions.

Brand Viscosity Price per quart
AMSOIL Signature Series Synthetic 5W-30 $12.05
Royal Purple High Performance Synthetic 5W-30 $8.72
Mobil 1 Extended Performance 5W-30 $11.49

Editor’s Note: AMSOIL Preferred Customers can receive up to 25% off retail prices when they sign up to join the program. After the potential 25% off discount, the price will drop to $9.04 per quart of oil.


Today, the leading brands of synthetic oil, including AMSOIL, Royal Purple, and Mobil 1 are almost identical. Since they are all API certified you can take confidence that they all meet industry performance requirements.

However, when it comes time to decide between all of the options available on the market there are 3 things to consider. These include the viscosity grade, drain interval and price.

As we mentioned, the most important factor when selecting an oil is buying the correct viscocity grade. Always refer to your owner’s manual to find out which viscosity you need.

The other factors to consider include the drain interval and price. In our research we discovered that AMSOIL had the longest drain interval at 25,000 miles. Royal Purple has a 12,000 mile interval and Mobil 1 Extended Performance is 15,000 miles.

With these factors in mind, it is up to you to decide which oil is right for your car or truck. Some people are very brand loyal while others are always looking for the best deal.

Just know that the leading brands of synthetic oil meet or exceed the API performance standards.

Which brand of synthetic oil do you use? Let us know in the comments below!