Finding the perfect fit is key to unlocking the full potential of your Ultrahuman Ring AIR or PRO.

A snug, accurate fit ensures maximum comfort and precise sensor readings – day and night.

What’s in the sizing kit?

Your sizing kit includes 10 sample rings, designed to help you find the right fit before choosing your final Ultrahuman Ring. It’s important to use this kit: Ultrahuman Ring sizes differ from standard rings and other smart rings.

Tip: You’ll receive the sizing kit when you order your Ultrahuman Ring AIR.

Watch the sizing guide video

Why sizing matters

The Ultrahuman Ring uses optical sensors on the inner surface to track your biometrics. For accurate readings, the sensors must stay in constant contact with your skin. A loose fit can cause light leakage, leading to gaps in your data.

Choosing the right fit ensures:

• Reliable biometric tracking
• All-day comfort
• Better performance insights

Three steps to choosing your ideal size

1. Choose your finger

Start by trying the ring on your index, middle, and ring fingers. Avoid the thumb or little finger. Try both hands.

2. Check the fit

• The ring should sit snugly at the base of your finger.
• The sensor ridge should be on the palm side.
• When you twist the ring, your skin should move with it.
• If the ring feels right, still test one size up and one down to be sure.

3. Wear for two nights

Keep your chosen size on for at least two nights. Finger size changes due to:

• Temperature
• Fluid retention
• Activity
• Menstrual cycle (for women)

Assess comfort during daily tasks and while sleeping. A snug fit on multiple fingers can offer flexibility—switch fingers if needed.

Still unsure? Try these tips

• Try multiple sizes on all fingers: index, middle, and ring on both hands.
• Pick fingers where the knuckle and base are similarly sized.
• If the larger size feels loose at any time, go with the smaller size.
• Prefer a fit that works on more than one finger for flexibility.
• Still stuck? Email support@ultrahuman.com for personalized help.

Final sizing checklist

• Ring fits snugly at the base of the finger
• Sensor ridge is on the palm side
• Skin moves with the ring when twisted
• Comfortable and snug after two nights of wear
• If you’ve checked all these boxes, you’re ready to submit your ring size.

How to submit your sizing preference

1. Scan the QR code inside the sizing kit.
2. Log in to the Ultrahuman App using the same email as your purchase.
3. Go to the Home tab and follow the sizing submission steps.

Make sure you’re using the latest version of the app from the App Store or Play Store.

Can’t find your order in the app?

Try these steps:

1. Tap the option to transfer your order to your current login email.
2. Log in using your Apple or Gmail ID.
3. Go to the “Ring” tab.
4. Tap ‘Not able to see your order’ and follow the prompts.

Sizing kit FAQ

1. What is the Ultrahuman Ring Sizing Kit?

It’s a set of plastic sample rings (sizes 5 to 14) that lets you find the best fit before you receive your actual Ring AIR.

Perfect sizing is essential for accurate biometric tracking and a comfortable fit. The kit includes a QR code for submitting your chosen size.

Important: Ultrahuman’s sizes are different from other normal and smart rings, so using the kit is essential.

2. Why is sizing important?

A poor fit ruins the experience. If the ring is too loose, it may spin or slide off. If it’s too tight, it’ll be uncomfortable and may compromise sensor accuracy. The sizing kit helps avoid that.

3. Which finger should I wear the ring on?

We recommend the index, middle, or ring finger. The index finger often gives the best sensor data. Avoid fingers with large knuckles that might distort sizing. You can wear the Ring on either hand.

4. How should the ring feel when it fits correctly?

• Snug at the base of the finger
• Doesn’t spin freely
• Requires a bit of effort to remove
• No discomfort after prolonged wear
• The sensors of the ring (the bump on the inner shell) should be facing the palm side.
• To take the ring off, you must push the bottom of the ring from below and then slide it out.

Watch our video on how to use the sizing kit to pick your perfect Ultrahuman Ring .

5. How do I use the sizing kit properly?

• Flip the ring so the size number faces your palm.
• Wear it on your chosen finger.
• Test it across two days: morning, evening, workout, sleep.
• Make sure the ring stays snug during all these scenarios.

6. What if I’m between two sizes?

• Wear both sizes for at least two nights to understand which size is best.
• Choose the tighter one if both are reasonably comfortable.
• Still torn? Choose the one that works on more than one finger.
• Reach out to Ultrahuman Support if you’re unsure.

7. Can I test multiple fingers?

Yes. Try different fingers and even different hands. You might prefer the index finger on your dominant hand, but if that’s not comfortable, another finger might suit you better.

8. Do I return the kit?

No. It’s yours to keep. You can also share it with friends. There’s a referral QR code in the kit that gives them 10% off their ring purchase.

9. How do I submit my ring size?

Scan the QR code inside the kit and follow the steps. You need to be logged in using the same email ID on the Ultrahuman App as your purchase email ID (as mentioned on your order confirmation email). You will find the option to submit your preferences under the ring tab. Be sure to be updated to our latest app version from the App/Play store! You’ll confirm the size and color, and then we will ship your Ring.

10. Can I change my size after submitting?

If you change your mind on sizing after submitting via the app, reach out to Ultrahuman support ASAP.

11. What happens after I submit my size?

Your personalized Ring AIR is manufactured and shipped. Expect delivery in 7-10 days.

12. Is the sizing ring identical to the final product?

The sizing kit is made from plastic and is slightly lighter. The actual ring is made of metal, so it may feel different — but the fit should remain the same if tested properly.

13. Why does my actual ring feel slightly different from the test ring?

Factors like temperature, humidity, hydration, and time of day can cause slight changes in finger size. Morning fingers = slightly swollen; cold hands = slimmer fingers. That’s why the 48-hour wear test matters.

15. What if I lose the sizing kit?

Contact Ultrahuman Support. In most cases, they’ll help you order another one (charges may apply).

16. Can I use someone else’s kit?

Yes — as long as you’re using it for your own sizing and submit your size with your own email/order details.

17. Is the sizing process different for men and women?

No—ring sizing works the same regardless of gender. The most common sizes for women are 6–8; for men, 9–11, but there’s variation. Always test.

Final Sizing Checklist

Before submitting your size, confirm

☑️ Ring fits snug at the base of your chosen finger

☑️ Size number is facing your palm

☑️ Ring doesn’t rotate freely on its own

☑️ You’ve worn it comfortably through two full days