The best smart rings under $100: what your money actually buys

The honest answer

This page could very easily have been a list of five rings with names you have never heard, each with a star rating and a buy button. Those pages exist in quantity. We are not going to write one, for a simple reason: this site's rule is that we do not rank a ring we cannot verify, and at that price there is nothing to verify.

That does not make your search unreasonable. Wanting a sub-$100 sleep tracker is completely sensible — the category's prices are high and the fees are worse. It just means the answer is not the one the search implies.

What we checked

We went looking for any ring under $100 from a maker with a real US presence and published specifications. The closest we found still is not close:

• RingConn Gen 2 Air — RingConn's own lowest-priced ring, listed below its Gen 2 and Gen 3 on RingConn's store (RingConn). Cheapest verifiable no-fee ring we cover, and well above $100.
• Renpho LYNX — a subscription-free ring from a brand with a real US catalogue, with a charging case and a 5ATM rating. Renpho's own US store and reviews put it around the same territory as RingConn's cheaper rings, not under $100 (Renpho US, Live Science review). We have not yet reviewed it and it is not one of our picks.
• Amazfit Helio Ring — now confirmed on sale in the US and reviewed in our Amazfit Helio Ring review, but it was never a sub-$100 product and it still isn't. It is the cheapest no-fee ring from a brand that publishes full specs, which is a different question from this page's.
• A discounted Oura Ring 4 — clearance was reported after Ring 5 launched, but it needs the same membership, which adds $209.97 over three years. More on that below.

Our best budget smart rings page ranks the genuinely cheap end of the verifiable market, with the fee arithmetic attached. This page is about the band below it.

What the sub-$100 listings actually are

Search a marketplace for a cheap smart ring and you will get results. They are typically unbranded or lightly-branded rings from sellers with no product website, no published specification sheet, no named app developer, no sizing kit and no study of any kind. Names rotate; listings appear and vanish.

We are not going to name and rank them, because naming one implies we checked it, and there is nothing to check. What we can do is tell you exactly what goes unverified when a ring has no company behind it — because those five unknowns are the product you would actually be buying.

The five things you cannot verify

1. Who runs the app, and where your sleep data goes. A sleep tracker is an app with a sensor attached. With no named developer and no privacy policy you can read, you do not know who holds a minute-by-minute record of when you sleep, when you wake and what your heart does at 3am. Our data privacy guide shows what a real policy says and what to look for.
2. Whether the numbers mean anything. Rings that have been studied still vary enormously: Herberger et al. (Scientific Reports, 2025) put three rings against polysomnography and found four-stage sleep accuracy ranging from about 35% to 53%, with Oura highest (Herberger et al.). A ring with no published study at all is not “probably about the same” — it is a blank. Our accuracy guide holds every study we use.
3. Whether it fits. Every established brand we cover states that its sizes differ from standard ring sizes and offers its own sizer; RingConn and Samsung include one free. A ring is a sensor pressed against an artery — loose is not a comfort problem, it is a data problem. Our sizing guide explains why, and sizing compared shows how far apart brands are.
4. Who answers for the battery. Smart ring batteries are sealed inside and not user-replaceable: RingConn says its batteries are “not designed for user replacement,” and Oura describes a “rechargeable, non-replaceable” cell. When one swells, you want a company that responds — read our battery swelling guide for what that actually looks like and why it matters.
5. Whether it can legally stay on sale. This category has real patent litigation in it. Oura has taken rivals to the US International Trade Commission; Ultrahuman's Ring AIR left the US market after a 2025 exclusion order, and Nexxbase, maker of the Luna ring, agreed to stay out of the US. RingConn settled with an Oura license in October 2025, so its position is clear. A seller with no legal footprint has no answer to this question at all.

Note that reviews do not solve any of the five. Under the FTC's endorsement guides, a marketplace star rating tells you about arrival-day satisfaction — it does not tell you whether a sleep stage estimate is right, or who will be running the app in two years.

What we would actually buy for under $100

One device, and it is the least glamorous thing on this site. A chest strap measures the two numbers that matter most for recovery — heart rate and beat-to-beat variability — more accurately than any ring at any price, and it costs a fraction of one.

Why the strap. When researchers wanted to know whether an Oura ring was telling the truth about heart rate and HRV, they strapped a Polar H10 to the same people and used it as the yardstick: “The Polar H10 was used as the criterion measurement” in Dial et al. (Physiological Reports, 2025), across 13 adults and 536 nights (Dial et al.). It transmits over Bluetooth and ANT+ so it pairs with a phone, a watch or gym equipment, runs on a CR 2025 coin cell rated around 400 hours so there is nothing to charge, stores a session of up to 30 hours on its own, and charges no subscription.

What it will not do. Nobody sleeps in a chest strap by choice, so it will not give you effortless nightly sleep staging. It is the right tool for morning HRV readings, workouts and — usefully — for checking any ring you buy later. Our chest strap roundup ranks the field and how to test your ring against a chest strap shows the method.

The trap a cheap ring hides

Getting a real ring closer to $100

Four legitimate routes, none of which involves an unverifiable listing:

• Buy the brand's cheapest model, not its newest. The RingConn Gen 2 Air is RingConn's own entry ring and keeps the things that matter — no fee, the same sizes as the Gen 2, iOS and Android, IP68 to 100 m, a free sizing kit, the same one-year warranty. It drops the charging case, sleep apnea monitoring and the titanium alloy shell. Read Gen 2 vs Gen 2 Air for the full list.
• Check HSA/FSA. RingConn states its rings can be bought with HSA/FSA funds through Flex, Samsung says the Galaxy Ring qualifies, and Oura calls Ring 5 HSA/FSA eligible. Pre-tax dollars can close a real gap, but the IRS excludes expenses “merely beneficial to general health” and your plan administrator decides. Our HSA/FSA guide covers the Letter of Medical Necessity route.
• Take a trade-in if you have something to trade. Samsung's US store has advertised instant trade-in credit on the Galaxy Ring, and Ultrahuman's buy page offers a trade-in against the Ring PRO.
• Wait for a real sale on a real ring. Hardware prices in this category move often, which is exactly why this site does not print them — every button here links to the live price. Checking a verified ring's price this week beats buying an unverified one today.

When cheap is genuinely fine

We are not sniffy about spending little. There are real purchases in this category well under $100, and we cover them:

• A sizing kit, if you want to know your size before committing. See the sizing guide.
• A silicone cover, if you lift and do not want your ring chewed up — our lifting page covers it.
• A charging case for a ring that did not come with one — chargers and cases.
• Nothing at all. If the honest answer is that you are not ready to spend what a verified ring costs, waiting is a better outcome than a drawer ornament. Our are smart rings worth it page argues both sides.