Get Oura Ring 5 if it comes in your size: it's the smallest Oura you can buy, 6.09mm wide and 2.28mm thick in titanium, with typically 6–9 days of battery.1 / 6
Fitness rings
Oura, Samsung Galaxy Ring, RingConn, Ultrahuman, Amazfit and COLMI. For a ring, the questions that matter are battery life, whether your size exists, what the app costs each month, and which phones it works with, so that is what each guide answers first.
Get Oura Ring 5 if it comes in your size: it's the smallest Oura you can buy, 6.09mm wide and 2.28mm thick in titanium, with typically 6–9 days of battery.
Get Oura Ring 4 if you need a size Ring 5 doesn't make: Ring 4 comes in 4 to 15, Ring 5 in 6 to 13 only.2 / 6
Buy Samsung Galaxy Ring only if you use a Samsung Galaxy phone: it needs one, and it adds sleep tracking and an Energy Score to Samsung Health.3 / 6
Get RingConn Gen 3 for a no-subscription ring that buzzes with health alerts and tracks vascular-health trends, from $349.4 / 6
Get Ultrahuman Ring AIR if light weight matters more than battery: it's 2.4 grams and 2.4 to 2.45mm thick, with no recurring fee for core data.5 / 6
Get the Amazfit Helio Ring if you wear size 8, 10 or 12 and use Zepp: it's $149.99, and Amazfit says no subscription is required.6 / 6
Photos from Amazon listings and Wikimedia Commons.
Disclosure: As an Amazon Associate I earn from qualifying purchases. See Affiliate disclosure. This guide summarizes the makers’ published specs below — we haven’t tested them ourselves. See Methodology.
Start here
2026
Oura Ring 4 Ceramic
Get Oura Ring 4 Ceramic if you want Ring 4 in ceramic: the same sensors and 4–15 size range in a zirconia shell, at $399 on sale or $499 list.
Oura Ring 5
Get Oura Ring 5 if it comes in your size: it's the smallest Oura you can buy, 6.09mm wide and 2.28mm thick in titanium, with typically 6–9 days of battery.
Oura Ring Gen3
Oura no longer sells Ring Gen3 or its charger, so new buyers should get Ring 5, or Ring 4 for sizes 4, 5, 14 and 15 instead.
Ultrahuman Ring PRO
Get Ultrahuman Ring PRO for battery and storage: up to 15 days a charge, 250 days of data on the ring and a case that adds up to 45 days.
2024
Other models
Amazfit Helio Ring
Get the Amazfit Helio Ring if you wear size 8, 10 or 12 and use Zepp: it's $149.99, and Amazfit says no subscription is required.
COLMI R02
Get the COLMI R02 if you wear a US size from 7 to 13 and want sleep, heart-rate and SpO2 tracking for $55.98 with no subscription.
RingConn Gen 2
Get RingConn Gen 2 if you find one in stock: it's slimmer than Gen 3, at 2.0mm and 2 to 3 grams, with sleep-apnea monitoring and no subscription.
RingConn Gen 2 Air
Get RingConn Gen 2 Air if you want the cheapest RingConn: $199 for sleep stages and 24/7 vitals with no subscription, but no sleep-apnea monitoring.
RingConn Gen 3
Get RingConn Gen 3 for a no-subscription ring that buzzes with health alerts and tracks vascular-health trends, from $349.
Samsung Galaxy Ring
Buy Samsung Galaxy Ring only if you use a Samsung Galaxy phone: it needs one, and it adds sleep tracking and an Energy Score to Samsung Health.
Comparisons
Amazfit Helio Ring vs Oura Ring 5
Amazfit Helio Ring costs $149.99 in sizes 8, 10 and 12 with no required subscription; Oura Ring 5 starts at $399 in sizes 6–13, is slimmer, typically lasts 6–9 days against Helio's 4, and needs a paid membership for the full app.
Amazfit Helio Ring vs Galaxy Ring
Samsung Galaxy Ring costs $399.99, needs a Galaxy phone and comes in sizes 5–15 with six or seven days of battery; Amazfit Helio Ring costs $149.99, works with iPhone or Android, and comes in sizes 8, 10 and 12 with up to 4 days.
Oura Ring 4 Ceramic vs Oura Ring 5
Oura Ring 4 Ceramic keeps sizes 4–15 and seven days of storage in a 5.1–8.1 g zirconia shell; Oura Ring 5 is smaller, from 2 g, in sizes 6–13, with typically 6–9 days of battery and three days of storage.
Oura Ring 4 vs Oura Ring 4 Ceramic
Oura Ring 4 Ceramic is Ring 4 in a zirconia shell: the same sensors, sizes and battery as titanium Oura Ring 4, but thicker and heavier, at $399 on sale against titanium's $349 start.
Oura Ring 4 vs Oura Ring 5
Oura Ring 5 is the smaller, slimmer ring, in sizes 6–13 from $399; Oura Ring 4 covers sizes 4–15 from $349 and stores seven days of data to Ring 5's three, with the same membership on both.
Oura Ring 4 vs Oura Ring Gen3
Oura no longer sells Oura Ring Gen3 or its charger, so Oura Ring 4, from $349, is the replacement: same membership, sizes 4 to 15 and published dimensions.
Oura Ring 4 vs Ultrahuman Ring AIR
Ultrahuman Ring AIR is the lighter ring with no subscription, while Oura Ring 4 lasts longer, charges faster and comes in more sizes but needs Oura's membership; both were listed at $349.
Oura Ring 5 vs RingConn Gen 3
RingConn Gen 3 is the cheaper ring, with no subscription and 10 to 14 days per charge; Oura Ring 5 costs more up front and charges a membership for its full app.
Oura Ring 5 vs Galaxy Ring
Oura Ring 5 works with iPhone or Android and keeps its full app behind a membership, while Samsung Galaxy Ring only pairs with a Galaxy phone and charges no membership; the rings cost $399 and $399.99.
Oura Ring 5 vs Ultrahuman Ring PRO
Oura Ring 5 is the thinner ring you can order now, from $399 plus membership; Ultrahuman Ring PRO costs $479 with its case, claims up to 15 days per charge and ships to the US from 10 October 2026.
Oura Ring Gen3 vs Galaxy Ring
Oura no longer sells Gen3 and charges for its membership; Galaxy Ring is $399.99 with no membership listed, but it only works with a Samsung Galaxy phone.
RingConn Gen 2 Air vs RingConn Gen 3
Gen 2 Air is RingConn's $199 titanium-steel ring with up to 10 days of battery; Gen 3, from $349, adds a vibration motor, a sleep-apnea pattern, vascular trends and size 15.
RingConn Gen 2 vs RingConn Gen 2 Air
Same 6.8 by 2.0 mm shape and sizing kit: Gen 2, from $299, adds titanium, sleep-apnea monitoring, 10 to 12 days and a charging case, while Gen 2 Air is $199 titanium steel with up to 10 days and a dock.
RingConn Gen 2 vs RingConn Gen 3
Gen 2 is RingConn's thinner 2.0 mm ring, from $299, with a battery that varies by ring size; the $349-and-up Gen 3 brings a vibration motor, vascular trends, size 15 and a universal charging case.
RingConn Gen 3 vs Galaxy Ring
RingConn Gen 3 starts at $349, works with iPhone or Android and is rated for 10 to 14 days; Galaxy Ring is $399.99, lasts 6 or 7 days and needs a Samsung Galaxy phone.
RingConn Gen 3 vs Ultrahuman Ring PRO
RingConn Gen 3 is from $349 with vibration alerts and 10 to 14 days of battery; Ultrahuman Ring PRO is $479 with up to 15 days, 250 days of storage and a charging case, on a US pre-order.
Galaxy Ring vs Ultrahuman Ring AIR
Galaxy Ring needs a Samsung Galaxy phone and charges in an included case; Ultrahuman Ring AIR works with iPhone or Android, is slightly thinner and charges on an open pad.
Galaxy Ring vs Ultrahuman Ring PRO
Ultrahuman Ring PRO works with any phone and claims up to 15 days for $479; Samsung Galaxy Ring needs a Galaxy phone and lasts 6 or 7 days for $399.99, but it isn't a pre-order.
Ultrahuman Ring AIR vs Ultrahuman Ring PRO
Ring PRO costs $479 to AIR's $349 and adds up to 15 days of battery, a charging case and 250 days of on-ring storage, in a heavier ring whose US shipping starts 10 October 2026.