The best smart ring for iPhone, with no monthly fee

Which smart rings work with iPhone

Most of them. Of the eight rings we track, six list iPhone support, one doesn't work with iPhone at all (Samsung's Galaxy Ring), and one, the Ultrahuman Ring PRO, doesn't state its phone requirements on any page we checked. The detail that actually decides things is the minimum iOS version, because that's what rules out an older iPhone:

• RingConn Gen 2 and Gen 2 Air: iOS 17.0 or newer, per RingConn's product pages (RingConn).
• RingConn Gen 3: works with iPhone and Android, per The Gadgeteer's review. We didn't find a minimum iOS version for Gen 3 in our sources, so check the app's App Store listing before you buy.
• Circular Ring 2: “iOS 15 and later” on Circular's homepage, the lowest requirement we found (Circular). An older Circular help page lists a different version; we use the current product wording.
• Oura Ring 5 and Ring 4: Oura says Ring 5 is “Available on iOS and Android.” We didn't find a minimum iOS version on the pages we checked.
• Samsung Galaxy Ring: Android 11 or newer only. No iPhone.
• Ultrahuman Ring PRO: Data unavailable. Ultrahuman's buy page, product page and US FAQ don't state phone requirements.

Your iPhone shows its iOS version under Settings, General, About. If it can't install iOS 17, the RingConn Gen 2 and Gen 2 Air are out, and Circular's lower requirement makes it the fallback. If you're on a current iPhone, every ring in our picks works, and the choice comes down to fees, evidence and battery. For the wider field, including rings that aren't iPhone-specific, see our ranking of the best smart rings without a subscription.

The rings iPhone owners should skip

Samsung Galaxy Ring. It's a no-fee ring with a charging case in the box, and its Amazon listing title says “No App Subscription,” which makes it look like a natural fit for this page. It isn't. Samsung supports the ring on Samsung Galaxy phones and on other brands' Android phones running Android 11 or newer (Samsung), and there's no iPhone support. If a Galaxy Ring is on your shortlist, our best smart ring for Android is the page for you.

Ultrahuman Ring PRO, until Ultrahuman says otherwise. We couldn't find its phone requirements on Ultrahuman's US buy page, product page or FAQ. Ultrahuman does publish iPhone support for the older Ring AIR, but that's a different model, and it isn't sold in the US after the 2025 import exclusion order. Don't assume one carries over to the other. Ring PRO is also a US pre-order from Ultrahuman's own store (“ships October 10th onwards” when we checked) and isn't on Amazon.com. If you want it, ask Ultrahuman about iPhone support before you pay. Our Ultrahuman Ring PRO review has the rest.

Amazfit Helio Ring. We couldn't confirm it's still sold in the US: Amazfit's US store pages for it returned 404 when we checked. We don't rank a ring we can't confirm you can buy.

What an iPhone owner pays over three years

“Smart ring for iPhone with no subscription” is really a question about one brand. Of the iPhone-compatible rings, only Oura charges a membership: $5.99 a month or $69.99 a year in the US, with one month included for new members. Without it, Oura says you'll only see your three daily scores (Readiness, Activity and Sleep), battery, basic profile, settings and the Explore content (Oura Support).

We lay out every brand's policy in what a smart ring really costs over three years, and the Oura plan on its own in what Oura's membership costs.

Which iPhone ring fits you

If you already know what matters most to you, here's the short route through the picks:

• A recent iPhone and you want the best no-fee all-rounder: RingConn Gen 2. The included case is the reason it beats the Air.
• You hate charging: RingConn Gen 3 has the longest claimed single charge here (up to 14 days), and Gen 2's case is rated at up to 150 days. Oura Ring 5 claims 6-9 days and ships without a case.
• You want the lowest cost of ownership: RingConn Gen 2 Air. No fee, and RingConn lists it below its other two rings.
• Your iPhone is stuck on iOS 15 or 16: Circular Ring 2, the only pick that lists a requirement below iOS 17. Buy it from Circular's store, and size it with care, since it runs about half a size large.
• Very small or very large fingers: RingConn Gen 3 runs 6-15, Gen 2 and Gen 2 Air 6-14, Circular 6-14 and Oura Ring 5 6-13. Oura's older Ring 4 covers 4-15 with the same membership. Our large and small sizes guide ranks rings by range.
• You want the most published evidence and will pay for it: Oura Ring 5, or Ring 4, the model the Dial study actually tested. Read the fee math above first.

How we ranked them

First, a pass-or-fail check: a ring made this list only if its maker (or, for Gen 3, a named reviewer) says it works with iPhone. That removed the Galaxy Ring and the Ultrahuman Ring PRO. Then we ranked what was left on our published ring rubric: cost of ownership over three years (30%), evidence of accuracy (25%), claimed battery (15%), sizing and fit (10%), data ownership (10%) and phone support (10%). Details are on our methodology page.

The order follows the scores. The three RingConn rings lead on no fee and long claimed battery. Circular ranks fourth on its low iOS requirement and no required fee, held back by having no published validation and being sold only on its own store. Oura Ring 5 ranks last despite the strongest evidence behind its predecessors, because the membership is the one cost on this page that never ends. We haven't worn or lab-tested these rings; every fact comes from a linked brand page, study or named reviewer.

The picks in context

1. RingConn Gen 2

The best ring for most iPhone owners who won't pay a fee. RingConn claims 10-12 days per charge and up to 150 days with the included charging case, and it asks for iOS 17.0 or newer. Sizes run 6-14 with a complimentary sizing kit, and it's rated IP68 to 100 meters. It's also the only no-fee ring we found with a chest-strap comparison of its own: a 2026 preprint (Tao et al., not peer-reviewed) found a heart rate bias of -0.42 bpm against a Polar H10 in seated athletes. The caveats: that study was seated and at rest, Gadgets & Wearables found the Gen 2 read heart rate high against a chest strap on runs, and its “90.7% Sleep Apnea Monitoring Accuracy” is RingConn's own claim, not a diagnosis. More in our RingConn Gen 2 review.

2. RingConn Gen 3

The newest RingConn and the longest claimed single charge among the rings on this page: up to 14 days (11-14 on RingConn's features page) and 150+ days total with its charging case. The Gadgeteer's reviewer got about 10 days with vibration alerts on. It comes in 10 sizes from 6 to 15 and adds Vascular Health Insights and Sleep Apnea Pattern Insights; RingConn says Gen 3 is “not a medical device.” It ranks second for two reasons: we found no published validation of Gen 3 itself, and no minimum iOS version in our sources. It also showed “Out of stock” on RingConn's own store when we checked, though Amazon listed it. See the RingConn Gen 3 review and RingConn Gen 3 vs Gen 2.

3. RingConn Gen 2 Air

RingConn's lower-priced ring (the brand lists it below Gen 2 and Gen 3), with the same iOS 17.0 requirement and the same 6-14 sizes as Gen 2. You get up to 10 days per charge and a 90-minute fast charge; you give up the charging case, sleep apnea monitoring (“it does not include sleep apnea monitoring,” per RingConn) and Gen 2's titanium alloy, as the Air uses titanium steel with a PVD coating. For an iPhone owner who just wants sleep and heart rate data with no fee, it covers the basics. Our Gen 2 vs Gen 2 Air comparison lays out the trade.

4. Circular Ring 2

The ring for an iPhone that can't update to iOS 17: Circular lists iOS 15 and later. It has no forced subscription, claims 8 days in power mode or 5 in performance mode, and lists single-lead ECG and AFib detection among its features, with Circular's own caveat that it “is not a diagnostic device.” It carries a one-year US warranty and 14-day returns. The drawbacks put it fourth: it's sold only on Circular's store, it runs about half a size larger than standard sizing by Circular's own note, we found no published validation of this model, and some future features will cost Circular Coins. Our Circular Ring 2 review and Circular Ring 2 vs Oura go deeper.

5. Oura Ring 5

If you want the ring with the most published evidence behind it and you'll pay for it, Oura works on iPhone. The best study we found, Dial et al. (Physiological Reports, 2025), compared Oura Gen 3 and Gen 4 with a Polar H10 across 536 nights in 13 adults and found the closest agreement of the wearables tested: resting heart rate error about 1.9% and HRV error about 6% for Gen 4. That study tested the previous generations, overnight only. Ring 5 claims 6-9 days per charge, and DC Rainmaker got 6-7 days. It ranks last here because of the membership. Our Oura Ring 5 review weighs the fee against the evidence, and Oura vs RingConn puts our top pick next to it.

iPhone questions we couldn't answer

People shopping for an iPhone ring also ask about Apple Health syncing, notifications and how the app looks on iOS. We didn't verify Apple Health integration or notification features for any of these rings from a brand page, so we don't claim them. If either matters to you, read the brand's app listing in the App Store before you buy; it states the compatibility requirement too, which is worth a second look because app requirements can change after we check.

We're equally careful with health features on iPhone. RingConn's sleep apnea numbers are its own claims, Circular's ECG comes with a “not a diagnostic device” caveat, and no Oura ring feature is FDA-cleared as of our check. Our smart ring sleep apnea guide covers what those features can and can't tell you.

What to check before you buy a ring for your iPhone

1. Your iOS version. RingConn Gen 2 and Gen 2 Air need iOS 17.0 or newer; Circular lists iOS 15 and later. Check Settings, General, About, then check the app's App Store listing on the day you buy.
2. Your size, measured with that brand's kit. No brand says its sizes match another's. RingConn offers a complimentary kit, and Circular runs about half a size large. Our smart ring sizing guide explains how to use one.
3. Whether a charging case is included. RingConn Gen 2 and Gen 3 include one; Gen 2 Air and Oura don't, and Circular doesn't state one.
4. Where you'll buy it. RingConn and Oura are listed on Amazon, so Amazon's return process applies. Circular is sold only on its own store, with 14-day returns.
5. The fee, if any. Only Oura requires one among iPhone rings. Our which rings require a subscription explainer lists every brand's policy.

iPhone ring mistakes

• Buying a Galaxy Ring for an iPhone. It won't work. It's Android only.
• Borrowing another model's specs. Ultrahuman's Ring AIR requirements don't tell you anything about Ring PRO, and Oura's Ring 4 sizes don't match Ring 5.
• Reading “no subscription” as “nothing to buy, ever.” Circular's future features may cost Circular Coins. Check whether a feature you want sits behind one.
• Buying your jewelry size. Smart ring sizes are brand-specific. Our smart ring sizing compared page shows why there's no official conversion between brands.
• Treating an apnea percentage as a diagnosis. It's a maker's claim about a screening feature. Talk to a clinician about symptoms.

Ring or smartwatch for an iPhone owner?

A ring has no screen and sits on a finger, and the published evidence for rings is strongest overnight, for sleep, resting heart rate and HRV. If you already wear a watch in the day, a ring can take the overnight shift. If you're choosing one device, our smart ring vs smartwatch comparison weighs the two on evidence and cost, and the smart ring comparison chart puts every ring's phone support in one table.