The best budget smartwatch under £100 is the Amazfit Bip 3 Pro for all-round value, thanks to built-in GPS, 14-day battery, and 5 ATM rating. If you prioritise a brighter AMOLED display, the Redmi Watch 4 is the best alternative when discounted to £99.
Quick verdict and why it wins
Amazfit Bip 3 Pro balances essentials better than rivals in this price band. It offers reliable GPS, long battery life, and dependable health tracking without bloat. Redmi Watch 4 is the best display-first option when you catch it at £89-99.
Which affordable smartwatches are reliable?
Reliability starts with stable firmware, consistent sensors, and proven battery endurance. In sub-£100 models, Amazfit and Xiaomi score well for week-long stamina and solid GPS locks outdoors. Realme and older Xiaomi models offer value, but firmware polish and water protection vary.
How we judged reliability
We looked for consistent heart rate accuracy at rest and during runs, GPS error below 3 to 5 percent on 5 km routes, and battery life that matches real-world use. We also checked 5 ATM water resistance for swimming versus IP68 splash resistance. Finally, we considered update cadence and app stability.
What features does a £100 smartwatch offer?
Expect all-day heart rate, SpO2 spot checks, sleep stages, notifications, music controls, and 100 to 150 sport profiles. Built-in GPS exists, but not on every model, and dual-band GNSS is rare at this price. LTE, ECG, skin temperature, and rich app stores are generally absent.
Top picks under £100 in the UK
Amazfit Bip 3 Pro - best overall
Typical UK street price sits around £60 to £70. You get a 1.69 inch display, built-in GPS supporting multiple constellations, 5 ATM water resistance, and up to 14 days of battery in typical use. Zepp app offers good historical charts, PAI scoring, and stress tracking.
Workouts start quickly, with GPS locks in 10 to 30 seconds outdoors. Heart rate and pace trends are consistent enough for beginner 5K to 10K training. Weaknesses include a basic TFT screen and no advanced training load metrics.
Redmi Watch 4 - best budget AMOLED
Often priced £89 to £99 during promotions, the Redmi Watch 4 brings a 1.97 inch AMOLED at 60 Hz with a bright 600 to 700 nit panel. Battery life is up to 20 days typical and 10 days heavy use. It carries 5 ATM water resistance and dependable notification handling.
GNSS is competent for city runs, though not dual-band, and cadence estimation is acceptable for casual training. Downsides are limited third-party integrations and occasional app sync delays. When it dips under £100, it is the easiest display upgrade you can buy.
Amazfit GTS 2 Mini New Edition - compact all-rounder
Commonly £69 to £89, the GTS 2 Mini NE uses a 1.55 inch AMOLED, offers built-in GPS, and lasts up to 14 days. It includes SpO2, stress, female health tracking, and 5 ATM water resistance. The case is lightweight at under 20 g without strap.
Sleep staging is detailed, and the always-on display option is present with a battery hit. The primary limitation is a smaller screen for text-heavy notifications. Training load metrics remain basic compared to higher tiers.
Realme Watch 3 Pro - GPS on a budget
Usually £60 to £75, the Watch 3 Pro includes a 1.78 inch AMOLED and built-in GPS. Battery runs 7 to 10 days depending on AOD and workouts. Bluetooth calling is supported with a decent speaker.
The trade-off is IP68 protection rather than 5 ATM, so it is not a swim watch. GPS is fine for parks and suburbs but can drift in dense streets. App analytics are improving yet remain simpler than Zepp or Huawei Health.
Xiaomi Watch 2 Lite - cheapest with GPS
Frequently £39 to £59, this older model still delivers built-in GPS and 5 ATM water resistance. Battery stretches to 10 days typical use. The 1.55 inch TFT is modest but readable.
As a starter watch, it covers daily steps, sleep, and basic runs well. Limitations include slower syncing and fewer watch faces. At the lowest prices, it is a strong first smartwatch.
How they compare with flagship watches
Against Apple Watch 11
Apple Watch 11 offers ECG, fall and crash detection, irregular rhythm notifications, temperature sensing, and seamless iOS integration. Its app store, Siri, and premium build are unmatched, but battery is typically 18 to 36 hours. Budget watches trade those features for multi-day stamina and much lower cost.
If you later upgrade, you can keep personal style consistent with Apple straps and complement with Apple accessories to refresh the look.
Against Samsung Galaxy Watch 8 and 8 Classic
Galaxy Watch 8 series delivers Wear OS apps, optional LTE, advanced running metrics, and high-grade AMOLED displays. Rotating bezel on Classic improves navigation and feel. Under £100, you will not get LTE, app stores, or high-end biometrics, but you will get longer battery life per charge.
Against Garmin Venu 3 and Forerunner 165
Garmin brings deep training analytics, Morning Report, Body Battery, HRV status, and excellent GPS. Venu 3 adds a bright AMOLED and long endurance, while Forerunner 165 targets runners with accurate pace metrics. Budget picks match only the basics, not the coaching and recovery insights.
Battery life and charging facts
Typical sub-£100 watches last 7 to 14 days with 24x7 heart rate and 3 to 4 GPS sessions per week. GPS-heavy users can expect 5 to 8 hours of continuous tracking on many models. Charging is usually a pogo-pin magnetic cable, filling 0 to 100 percent in 90 to 150 minutes.
Health and GPS accuracy expectations
Optical heart rate sensors are most accurate at rest and steady paces. Interval spikes can lag by 2 to 5 seconds, with max HR sometimes under-reported by 2 to 5 bpm. GPS tracks are typically within 2 to 5 percent distance variance on mixed routes without tall buildings.
Connectivity and notifications
Bluetooth 5.0 to 5.3 is common, supporting stable pairing and quick sync. You get call, text, and app alerts, with Android enabling more granular replies than iOS in most budget apps. Music storage and NFC payments are largely absent below £100.
Fast shortlist by needs
- Best overall: Bip 3 Pro
- Best display: Redmi Watch 4
- Small wrist: GTS 2 Mini
- Cheapest GPS: Watch 2 Lite
- Calls onboard: Watch 3 Pro
Key specs table under £100
| Model | UK price | Display | Battery claim | GPS | Water rating | Notable trade-offs |
|---|---|---|---|---|---|---|
| Amazfit Bip 3 Pro | £60-70 | 1.69 inch TFT | Up to 14 days | Built-in GNSS | 5 ATM | Basic screen, no apps |
| Redmi Watch 4 | £89-99 | 1.97 inch AMOLED | Up to 20 days | Built-in GNSS | 5 ATM | Limited integrations |
| Amazfit GTS 2 Mini NE | £69-89 | 1.55 inch AMOLED | Up to 14 days | Built-in GNSS | 5 ATM | Small screen text |
| Realme Watch 3 Pro | £60-75 | 1.78 inch AMOLED | Up to 10 days | Built-in GPS | IP68 | No swim tracking |
| Xiaomi Watch 2 Lite | £39-59 | 1.55 inch TFT | Up to 10 days | Built-in GPS | 5 ATM | Older software |
Buying tips that matter
Prioritise battery and GPS
If you run outdoors, built-in GPS is worth it even with a basic screen. Without GPS, connected tracking can drain your phone faster and reduce accuracy. Choose 5 ATM if you plan to swim.
Screen and comfort count
AMOLED improves readability and watch faces, but TFT models can save £20 to £30. Aim for under 35 g for comfort in sleep tracking. Silicone straps are best for workouts, leather for daily wear.
Upgrade path awareness
If you later move to Apple Watch 11 or Galaxy Watch 8, your fitness data exports and habits still help. Starting with a budget watch builds routine at low cost. Prioritise ecosystems that allow data export to Apple Health or Google Health Connect.
Limitations to expect
- No ECG or LTE
- Limited third-party apps
- Basic training metrics
- Fewer watch faces
- Occasional sync delays
FAQ
Can I swim with a £100 smartwatch?
Yes, if it is rated 5 ATM, such as Amazfit Bip 3 Pro, GTS 2 Mini, or Redmi Watch 4. IP68 models are for splashes and rain, not pool sessions. Always check the official rating before swimming.
How accurate is the heart rate sensor?
At rest and steady paces, readings are within 2 to 4 bpm of a chest strap. During high-intensity intervals, lag can cause 3 to 7 bpm differences. Tight, comfortable strap fit improves results.
Do these watches support iPhone and Android?
Yes, Amazfit and Xiaomi support both platforms with full basics. Quick replies are better on Android than iOS in many budget apps. App stores and voice assistants are limited compared to flagships.
Is built-in GPS necessary?
For runners and cyclists, it improves accuracy and phone-free tracking. If you mostly walk or treadmill, connected GPS may be enough. Built-in GPS also preserves phone battery on long routes.
Will I miss advanced features?
You will miss ECG, LTE, app ecosystems, and deep coaching. Most people gain longer battery life and lower costs in exchange. If you need advanced metrics, consider Apple Watch 11, Samsung Galaxy Watch 8, or Garmin Forerunner 165 later.
Conclusion
The best budget smartwatch under £100 is the Amazfit Bip 3 Pro for its balance of built-in GPS, 14-day battery, 5 ATM rating, and reliable health tracking. For a brighter AMOLED and premium feel under £100, choose the Redmi Watch 4 when on sale. Both deliver the essentials at excellent value.
