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Xiaomi Mi Smart Band 8

A slim fitness and health tracker wristband (Global Version) with a 1.62" AMOLED touchscreen, 150+ sports modes, and optical sensors for heart rate, blood oxygen (SpO2), sleep, and stress monitoring. Rated by Xiaomi for up to 16 days of battery life on a single charge. Syncs to the Mi Fitness app over Bluetooth. Xiaomi's Mi/Redmi Band line is one of the best-selling fitness-tracker families worldwide.

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1.62" AMOLED · 16-day battery

Sold at major US retailers,
including Amazon

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We don't display a fixed price here since Amazon pricing changes — click through to see the current price before buying. This is the Global Version, which ships with a multi-language interface (including English) — a separate China/CN version exists with different default language and app pairing, so check the listing carefully before buying.

Governed by the retailer's own return policy at time of purchase

Specs & features

Full technical specifications as published on Xiaomi's own global product/specs pages — nothing added, nothing hidden.

Specs & Features

Version: GlobalConnectivity: Bluetooth 5.1 BLE

Specification	Detail
Display	1.62" AMOLED touchscreen, 60Hz refresh rate
Battery capacity	190mAh
Battery life	Up to 16 days typical use (manufacturer-stated)
Charging	Magnetic charging cradle, ~1 hour full charge
Sports modes	150+
Health sensors	Optical heart-rate sensor, SpO2 (blood oxygen) sensor, sleep monitoring, stress monitoring
Water resistance	5 ATM
Connectivity	Bluetooth 5.1 BLE, Mi Fitness app
Phone compatibility	Android 6.0+ or iOS 12.0+

Every spec above is as published on Xiaomi's own global product and specs pages for the Smart Band 8 (not the "Active" or "Pro" variants, which have different displays and battery specs). Xiaomi's own support materials state this device "is not a medical device" and that its health readings "are for information purposes only" — see the FAQ below for what that means for the heart-rate and SpO2 sensors specifically.

Manufacturer

Xiaomi

Country of origin

Not independently confirmed — not disclosed on the Amazon listing

Version

Global (multi-language)

This is a small electronics device, not a multi-ingredient product — there's no "proprietary blend" to disclose. Every spec above is manufacturer-published; we've flagged the one detail (country of origin/factory) that isn't disclosed on the listing rather than guessing at it.

How it works

What the optical sensors actually measure, and how accurate they really are — not a claim about what this specific unit will do for you.

Optical heart-rate and SpO2 sensing

Like nearly all consumer fitness bands, the Mi Smart Band 8 measures heart rate and blood oxygen using PPG (photoplethysmography) — LEDs on the underside of the band shine light into the skin, and a photodetector measures how much light is absorbed and reflected as blood volume changes with each heartbeat. Blood oxygen saturation is estimated from how differently oxygenated versus deoxygenated blood absorbs different wavelengths of light. This is the same basic technology used in the SpO2 finger clips found in medical settings, but implemented with a smaller, wrist-worn, lower-cost optical sensor rather than a purpose-built clinical instrument — and Xiaomi's own materials state plainly that this device is not a medical device and its readings are for informational purposes only.

How accurate is it, really?

Peer-reviewed validation research on the Xiaomi Mi Band lineage gives a mixed picture. A 2022 study in Annals of Rehabilitation Medicine compared the Mi Band 5 to ECG in cardiac patients during exercise testing and found strong correlation (rc > 0.90) with ECG at rest and low-intensity exercise, but reported all tested consumer bands became less accurate during moderate-to-high-intensity effort. A 2026 study in Sensors testing the Mi Band 6's SpO2 and heart-rate readings against a clinical pulse oximeter in children and adolescents with severe cerebral palsy found heart rate had good reliability (ICC 0.83) for general monitoring, but SpO2 readings had low reliability (ICC 0.55) and error margins that exceeded clinically acceptable accuracy — the authors concluded the device was "not suitable for assessing SpO2" in that population. Neither study tested the Smart Band 8 specifically, and the cerebral-palsy study is a narrow clinical population that may not generalize to healthy adult wrist-band use — but taken together, the evidence supports treating this band's heart-rate readings as reasonably useful for general activity tracking at rest and moderate effort, and its SpO2 readings as directionally informative at best, not a substitute for a real pulse oximeter.

Scientific references

The studies below back the accuracy notes above — clickable, so you can read the original source yourself rather than take our summary on faith.

Kim C, Kim SH, Suh MR. Accuracy and Validity of Commercial Smart Bands for Heart Rate Measurements During Cardiopulmonary Exercise Test. Annals of Rehabilitation Medicine. 2022;46(4):209-218. doi:10.5535/arm.22050. PubMed →
Guerrero-Blázquez A, Álvarez-Melcón ÁC, López-Marcos JJ, Martín-Casas P, Arranz-Escudero A, Ortiz-Gutiérrez RM. Validity and Reliability of a Smart Band for Monitoring Cardiorespiratory Parameters in Children and Adolescents with Severe Cerebral Palsy. Sensors. 2026;26(3):828. doi:10.3390/s26030828. PMC →

Frequently asked questions

Is the blood oxygen reading medical-grade?

No. Xiaomi's own support materials describe the band as not a medical device, with health readings intended for informational purposes only, not diagnosis or treatment. Validation research on the Mi Band lineage (see Scientific references above) has found SpO2 readings noticeably less reliable than a clinical pulse oximeter, particularly outside of resting, stable conditions. Treat the SpO2 number as a rough, directional data point, not a clinical measurement.

How accurate is the heart-rate sensor during exercise?

Research on this device family shows the strongest agreement with ECG at rest and during low-to-moderate intensity exercise, with accuracy dropping off at higher intensities — a pattern common to virtually all optical wrist-based heart-rate sensors, not unique to this product. It's reasonable for general activity and cardio tracking; it's not a substitute for a chest-strap monitor or clinical ECG if you need precise numbers during intense training.

How long does the battery actually last?

Xiaomi rates it at up to 16 days under typical use. Actual runtime will be shorter with heavier use of the always-on display, GPS-connected workouts, frequent notifications, or continuous SpO2/heart-rate tracking — none of which we've independently benchmarked ourselves.

Does it work with an iPhone?

Yes — per Xiaomi's published specs, it's compatible with iOS 12.0 or later, as well as Android 6.0 or later, via the Mi Fitness app over Bluetooth 5.1.