Xiaomi Watch S4

Home » Specs » Xiaomi » Watch S4

Full specifications, features and battery life for the Xiaomi Watch S4, the brand’s style-led smartwatch with dual-frequency GNSS, sold in 47mm and 41mm sizes.

Specifications and features as at launch.

Xiaomi Watch S4

Dual-frequency GPS, running form metrics and contactless payments, with up to 15 days between charges.

RRP £129.99 £104.99

€126.99

- use code:

Get it nowOrder now – Xiaomi Watch S4 Also sold direct by

Xiaomi Watch S4 41mm

A 32g watch for smaller wrists with dual-frequency GPS, contactless payments and heart rate broadcast to a bike computer.

RRP £134.99 £124.79

€133.31

- use code:

Get it nowOrder now – Xiaomi Watch S4 41mm Also sold direct by

Expert opinion | Specifications | Battery life | Features | Further reading

Expert opinion

Watch S4 is Xiaomi’s style-led watch with a capable sports core in both sizes: more than 150 sports modes, dual-frequency GPS that stays accurate in cities and under trees, a barometer for climbing, a 5 ATM rating for the pool, NFC payments and Bluetooth calls. The two sizes differ in more than diameter. The 41mm runs newer software and adds live heart rate while swimming, training load and recovery time, heart rate broadcast to bike computers, a skin temperature sensor and emergency SOS. The 47mm has swappable bezels, running form feedback and on-wrist running courses, and it is the one to pick for battery: Xiaomi claims 15 days of typical use against up to 8 days of light use for the 41mm. Neither has ANT+ or offline maps, and data leaves through Health Connect, Suunto and, on the 47mm, Strava. Choose the 47mm for battery life and the 41mm for a smaller wrist or the richer training metrics. Both undercut a Garmin Forerunner 165 while offering better positioning hardware.

Specifications

Battery life

Xiaomi does not publish a continuous GNSS figure for either size, so the useful comparison is the smartwatch claims. The 47mm model’s 15 days assume 90 minutes of recorded exercise a week, heart rate every 10 minutes, and all-day blood oxygen, stress and high-precision sleep tracking switched off. The 41mm model’s 8-day light-use claim uses a similar weekly routine with GNSS on, and its normal-use figure of 4 days switches those all-day health features on and doubles exercise to 180 minutes a week. An athlete training most days with full health tracking should therefore expect to charge the 41mm twice a week. The 47mm should stretch well past a week on the same routine, and its quick top-up of 2 days from 5 minutes on the charger covers a forgotten charge before a race.

Features

Full feature detail is covered on the Xiaomi specifications index.

Sport and training

• Both sizes track outdoor runs and rides on their own GNSS, with dual-frequency L1 + L5 positioning and better resistance to signal interference.
• More than 150 sports modes cover running, cycling, swimming and gym work, plus a professional skiing mode that records each run’s distance, speed and turns.
• The 47mm model offers on-wrist running courses for goals from beginner fitness to endurance, and running form recognition reports vertical ratio, vertical oscillation and ground contact time.
• The 41mm model shows heart rate in real time while swimming, and its post-workout report adds a heart rate curve, aerobic and anaerobic training effect, load, recovery time and perceived exertion.
• The 41mm model can broadcast heart rate over Bluetooth to bike computers that accept BLE heart rate, and Xiaomi names Garmin Edge 540 and 840, Bryton and Magene units.
• Sports vlog on the 41mm starts video recording on the phone during exercise, with heart rate and calories overlaid, on Xiaomi and POCO phones only.

Health and recovery

• One-tap health insights give a reading of heart rate, blood oxygen, stress and sleep in around 60 seconds.
• All-day blood oxygen, stress and advanced sleep monitoring can be switched on, at a cost to battery life.
• The 41mm model tracks skin temperature trends in steps as small as 0.1 degrees C, alerts on high readings, and uses the data to improve menstrual cycle predictions.
• The 41mm model adds a sleep improvement plan covering sleep schedule, naps, daytime activity and pre-bed relaxation.
• Guided breathing exercises help with relaxing, concentrating, napping and sleep.

Safety

• Fall detection while skiing calls an emergency contact if there is no response within 60 seconds of the alarm.
• The 41mm model adds Emergency SOS with three presses of the lower button, a loud siren, and live location sharing with emergency contacts, which requires an Android phone.

Smart features

• Bluetooth calls can be answered on the wrist through the built-in speaker and microphones while the phone is connected.
• NFC payments with Mastercard and Visa leave the wallet at home on a run, depending on bank and region.
• The rotating crown scrolls through widgets and message previews without covering the screen.
• The 47mm model’s bezels swap for optional ceramic, carbon and stainless steel designs, some of which unlock matching watch faces such as a second time zone.
• Xiaomi Smart Hub controls a Xiaomi phone, earbuds and smart home devices from the watch, but only with supported Xiaomi phones and tablets.

Compatibility

• The Mi Fitness app works with Android 8.0 or later and iOS 14.0 or later.
• Workout and health data can sync to Health Connect and Suunto on both sizes, and Xiaomi also lists Strava for the 47mm model.

Further reading

• Xiaomi specifications index
• Xiaomi Watch S5 specifications
• Xiaomi Watch 5 specifications
• REDMI Watch 6 specifications
• Sports watch specifications