Oura Ring Size Vs Regular Ring Size: Find Your Perfect Fit

There has been a lot in the air regarding the Oura ring sizes and whether they are any different from standard ring sizes. Well, in the beginning, I had no clue about it until I stumbled on something called the “Oura ring sizing kit.” That is how I got an answer to the much-hyped question: Oura Ring size vs regular ring size, what’s the difference?

An Oura ring, say, size 6, is not identical in dimensions to a regular ring of the same size. So, if you try to guess the size of your Oura ring based on your regular ring size, you will most certainly end up with a ring that doesn’t fit you well.

This became even more important with the new Oura Ring 4 sizes. Why? Because the Ring 4 is new and also differs from the Gen 3 sizes. The Ring 4 uses sizes 4-15 while the Gen 3 uses 6-13. So, in order to get a snug fit and accurate tracking, the safest option is to use the correct Oura Ring sizing kit and wear the test ring for at least 24 hours before deciding on the right size for you.

Also, with something that burns at least three hundred dollars out of my pocket, that’s not a risk I would want to take.

Are Oura Ring Sizes the Same as Regular Ring Sizes?

No, Oura Ring sizes are not the same as standard US ring sizes. Oura uses whole numbers for their sizes, not half sizes. Also, Oura Ring Gen 3 sizes differ from the Ring 4, not just in the range of sizes they carry, but also in their dimensions.

Oura ring size is slightly larger than a standard US ring size. To give you a general idea, let me use Oura Gen 3 ring size 6 as an example to explain the math behind it. It has an inner diameter measuring 16.76 mm. A typical ring of the same size, however, has an inner diameter of 16.50 mm. 

On the other hand, the inner diameter of Oura Ring size 6 with sensor bumps comes to around 15.21mm, which is less than a standard US ring diameter of the same size (16.50mm). So, although the Oura Ring of size 6 would look bigger on the finger, it will be tighter than a standard ring of the same size.

Oura Ring Size vs Regular Ring Size

Oura Ring Gen 3 Sizes vs Standard US Ring Sizes

Ring Size	Oura Ring Gen3 Inner Diameter With Sensor Bumps [Actual]	Oura Ring Gen3 Full Inner Diameter	Oura Ring Gen3 Circumference	Standard US Ring Size Inner Diameter	Standard US Ring Size Circumference
6	15.21 mm	16.76 mm	52.6 mm	16.5 mm	51.8 mm
7	15.97 mm	17.60 mm	55.3 mm	17.3 mm	54.3 mm
8	16.81 mm	18.43 mm	57.9 mm	18.1 mm	56.9 mm
9	17.63 mm	19.25 mm	60.5 mm	18.9 mm	59.4 mm
10	18.41 mm	20.02 mm	62.9 mm	19.8 mm	62.2 mm
11	19.24 mm	20.81 mm	65.4 mm	20.6 mm	64.7 mm
12	20.05 mm	21.64 mm	68.0 mm	21.4 mm	67.2 mm
13	20.90 mm	22.48 mm	70.6 mm	22.2 mm	69.7 mm

Oura Ring 4 Sizes vs Standard US Ring Sizes

Ring Size	Oura Ring 4 Inner Diameter With Sensor Bumps [Actual]	Oura Ring 4 Full Inner Diameter	Oura Ring 4 Circumference	Standard US Ring Size Inner Diameter	Standard US Ring Size Circumference
4	14.10 mm	14.70 mm	46.18 mm	14.86 mm	46.68 mm
5	15.09 mm	15.52 mm	48.76 mm	15.70 mm	49.32 mm
6	16.01 mm	16.35 mm	51.37 mm	16.76 mm	52.65 mm
7	16.75 mm	17.13 mm	53.82 mm	17.60 mm	55.29 mm
8	17.59 mm	17.95 mm	56.39 mm	18.43 mm	57.90 mm
9	18.40 mm	18.72 mm	58.81 mm	19.25 mm	60.48 mm
10	19.07 mm	19.55 mm	61.42 mm	20.02 mm	62.89 mm
11	20.03 mm	20.35 mm	63.93 mm	20.81 mm	65.38 mm
12	21.01 mm	21.25 mm	66.76 mm	21.64 mm	67.98 mm
13	21.73 mm	22.05 mm	69.27 mm	22.48 mm	70.62 mm
14	22.45 mm	22.73 mm	71.41 mm	23.32 mm	73.26 mm
15	23.34 mm	23.70 mm	74.46 mm	24.16 mm	75.90 mm

Can you use your Gen 3 size for Ring 4?

If you are upgrading from your Oura Ring Gen 3 to the new Oura Ring 4, you might be thinking that you can just get the same size as you were wearing before. Hold that thought because while the Gen3 supports sizes 6-13, the Ring 4 has expanded their size range to 4-15. 

With this expanded size range, the sizes of the ring slightly differ as well. They might not be very noticeable to some people but it is best to get the sizing kit and wear the sample size for at least 24 hours before deciding what size you’re going for.

These rings are specially designed so that customers can find their best fit. There are a few important things to take note of while checking the ring size, like the hand you would like to wear it on, the finger, the snug test, etc.

However, it’s important to note that Oura does not offer half sizes like 6.5, 7.5, etc, or custom sizes. So there might be instances where an Oura ring of size, say 7 might be very tight on your finger, whereas an Oura ring of size 8 might feel a bit loose. 

But, if in case you are unable to get a hold of the sizing kit, the above dimensions as to how Oura sizes their rings, as compared to standard US ring sizes, is a good guide to help you.

Should You Size Up or Size Down for Oura Ring?

In case you find indents on your fingers after wearing your Oura Ring for long or it causes numbness or you experience difficulty in removing it, it’s probably too tight.

On the other hand, if the ring spins freely, the sensors shift frequently or there is a visible gap when you make a fist, your ring is probably too loose.

If one size feels too snug and the next size feels a little loose, try switching fingers and go for the slightly larger size if the smaller one feels restrictive or uncomfortable during swelling. This is because Oura doesn’t provide half sizes. 

Which Finger Should You Wear the Oura Ring On?

Best finger for accuracy

Oura recommends wearing the ring on your index finger of your non-dominant hand. Personally, I wear mine on my middle finger and switch between my ring finger too in case it feels tight after a sodium-heavy Chinese takeout dinner the previous night. 

Since the ring needs to be snug and can’t be exchanged, no matter which phase of life you are in, I have also seen some people wearing it on their thumb or their pinky finger while they’re pregnant. Aim for the perfect size of your pointer or middle finger and switch whenever necessary.

Why knuckle size matters

Ok here is the tricky part. If you have bigger knuckles, the ring might slide through but sit very loosely at the base of your finger, resulting in inaccurate readings.

In that case, don’t just stick to your index or middle finger, try on the sizes on other fingers too to see which one fits you the best.

How to Use the Oura Sizing Kit Properly

Use the correct generation kit

If you’re upgrading from Gen 2 or Gen 3 to the Oura Ring 4, the same sizing kit does not apply. The rings have different interiors and size ranges, so use the sizing kit from the generation you are looking to buy.

The Oura Ring Gen3 sizing kit comes with black sizers in sizes 6-13 and the Oura Ring 4 sizing kit comes with white sizers in sizes 4-15.

Test more than one finger

Make sure to test the sizers on your index finger, middle finger as well your ring finger, throughout the day and night to see which one you are most comfortable with.

Wear the sizer for at least 24 hours

Because our fingers may swell up or slightly fluctuate throughout the day and night, it is recommended to wear the sizing ring for at least a full day and night. This may be because the ring size may change due to sleep, exercise, weather, high salt/alcohol intake.

Make a fist to check for gaps

To check if the size you selected is correct, wear it and make a fist. If you see a visible gap between the ring and your finger, you may need to size down.

Signs Your Oura Ring Is Too Tight

• Numbness in finger
• Deep indentations from ring
• Ring is hard to take off
• Finger swelling at night
• Uncomfortable wearing the ring while exercising
• The tightness becomes painful during hot weather

Signs Your Oura Ring Is Too Loose

• Constantly spinning ring
• Shifted sensors from palm side
• Gap when making a fist
• Unusual sleep or heart rate readings
• Ring seems like it’s slipping during hand washing

Common Oura Ring Sizing Mistakes

Ordering your normal ring size without testing

While Oura Ring sizes are similar to their previous generations or even the standard US ring sizes, they are not identical. 

Testing the sizing kit for only a few minutes

Because your fingers might swell up during the day due to various factors like salt/ alcohol intake, exercise, weather conditions, etc., wearing your sizing ring for a few minutes will not give you an accurate size.

Ignoring finger swelling

As I said before, finger size may change naturally due to various factors and should be considered while selecting your ring size.

Choosing the ring finger only because it feels familiar

The best fingers for a smart ring are usually the pointer or the middle finger. Don’t just choose your size based on your ring finger because that’s where you normally wear your rings.

Using a Gen 3 sizing kit for Ring 4

Oura Ring sizes differ slightly from one generation to the other. Make sure to choose the sizing kit of the generation you are buying.

Forgetting Oura has no half sizes

If you feel like one size is a little too tight and the next is a little too loose, remember that Oura does not carry half sizes. This makes testing with your sizing kit especially important.

What If Your Oura Ring Does Not Fit?

In case even after all the testing, your final Oura Ring size feels off, you can request a one time exchange through Oura’s self-service portal. If the purchase was made through retailers such as Amazon, Best Buy, Costco or Target, the exchange/return policies will differ from Oura’s.

Do not confirm your Oura Ring size if:

• You have only tested the sizing ring for a few minutes or hours.
• You haven’t tried the sizer on multiple fingers.
• You didn’t wear the sizing ring overnight.
• You used the wrong generation sizing kit.

Frequently Asked Questions

What if The Ordered Oura Ring Size Doesn’t Fit Well?

The ordered ring that does not fit well can be returned for a full refund or exchanged for a different size. However, the return and exchange can happen only once per item.

Are Oura Ring Sizes the Same as Regular Ring Sizes?

No. Oura Ring sizes are similar to standard US ring sizes, but they are not identical because Oura Rings use internal sensors and require a snug fit.

Does Oura Ring run big or small?

Oura Ring looks slightly bigger than traditional jewelry rings because of the sensors and wider design.

Can I use my normal ring size for Oura Ring?

No, you have to get a dedicated sizing kit to check the size for Oura Ring. If you are unable to get a hold of the sizing kit, you can refer to our sizing table guide above.

Should I size up or down for Oura Ring?

If you are in between sizes, a slightly snug fit is generally recommended for proper readings as long as it remains comfortable.

Does Oura Ring have half sizes?

No, Oura does not carry half ring sizes.

What size is Oura Ring 4 available in?

Oura Ring 4 is available in sizes 4-15.

Is Oura Ring 4 sizing different from Gen 3?

Yes, Oura says Ring 4 sizing differs slightly from Gen 3 sizing, so users should use the correct Ring 4 sizing kit.

Which finger should I size for Oura Ring?

Oura recommends the pointer finger of your non-dominant hand for the best accuracy, although the middle and ring fingers may also work well.

How tight should Oura Ring be?

The Oura ring should feel snug but comfortable. It should not spin freely or cause numbness.

How long should I wear the Oura sizing kit?

You should wear the Oura Ring sizing kit for at least 24 hours, including overnight testing.

What if I am between two Oura sizes?

Test both sizes overnight and choose the fit that feels secure without becoming uncomfortable.

Can I exchange my Oura Ring if the size is wrong?

A one time exchange is available via a self service portal, directly through Oura. If the ring was purchased via a retailer, the exchange will depend on their policy. Always verify the latest return and exchange terms before purchasing.

Wrap Up

Wearing the Oura Ring for the first time feels awkward. I also felt that my finger (left-hand index finger) took some time to gel with the ring. But gradually, I got accustomed to it, and now it feels pretty normal.

If you take anything from this article, remember, a properly fitted Oura Ring should rotate with slight resistance and should not spin freely during normal movement.

When I decided to buy the ring, I thought I would just measure my ring size with some measuring tape, etc., and go ahead and get the ring directly. But, the sizing kit is free when you order from Oura directly, and the process of getting it and then going back to update the order is not very lengthy, and very important.

If you get the sizing kit, spend some time with the plastic ring sizers, and then get the actual Oura ring, it’ll be a seamless journey! I got the best fit, and my health-tracking journey has been going pretty smoothly from then on.