Fitbit Charge 6 Review: Good Idea, Uneven Execution
Our full Fitbit Charge 6 review after two weeks of testing: measured performance, battery figures, and whether it is worth £139.
Tech Daily Review Desk
The short version
The Fitbit Charge 6 is Fitbit's 2023 entry in a crowded wearables market, and at £139 it is competing against some of the strongest hardware we have tested. After a fortnight of daily use, the headline is straightforward: it delivers a genuinely low price for ECG and SpO2.
In a sentence: Buy it for a genuinely low price for ECG and SpO2. Think twice if this would bother you daily: a cramped display.
In the hand
There is nothing experimental here, which is mostly to the Fitbit Charge 6's credit. The detail worth calling out is that it is the cheapest way to get a usable ECG on your wrist. Against the rest of the wearables category it feels considered rather than novel.
Performance
Our testing runs the same suite on every device so figures stay comparable across years. The figure worth quoting is Weight: 38g. That places it mid-table at best for its price bracket.
| Specification | Fitbit Charge 6 |
|---|---|
| Display | 1.04in AMOLED |
| Battery | 7 days |
| Sensors | HR, ECG, EDA, SpO2 |
| Rating | WR50 |
| Weight | 38g |
How we tested
Every figure quoted above comes from the same protocol, run on every unit in this category. This one spent three weeks worn continuously, including overnight. Worn on the non-dominant wrist alongside a chest-strap heart rate monitor and a second reference watch, with all figures logged from the same sessions.
| What we measure | How |
|---|---|
| Heart rate accuracy | Beat-by-beat comparison against the chest strap across steady runs, intervals and weights. |
| GPS accuracy | The same 5km loop, twelve times, compared against a surveyed route. |
| Battery life | A fixed daily pattern — one hour of GPS exercise, always-on display, sleep tracking — run to empty. |
| Sleep tracking | Compared against a manual log of actual sleep and wake times over fourteen nights. |
| Durability | Worn through cooking, washing up and the gym, with no attempt to protect it. |
We deliberately do not report step counts, which every device on the market gets close enough that the differences are noise.
The honest caveat: Wrist-based heart rate is least accurate exactly where people care most — high-intensity intervals.
What it does well
- A genuinely low price for ECG and SpO2
- A week of battery
- Small enough for narrow wrists
Taken together, those strengths make it a natural fit for first-time trackers who want the basics done well.
What we did not like
- A cramped display
- A Premium paywall on most analysis
- A proprietary charger
None of these are dealbreakers on their own. Whether they matter depends entirely on how you intend to use it, which is why the section below matters more than the score.
How it compares
The closest alternatives on price are Whoop 5.0 and Amazfit T-Rex 3. All three have been through the same tests, so the figures below are directly comparable rather than collected from different reviews.
| Model | Price | Our score | Standout | Weak point |
|---|---|---|---|---|
| Fitbit Charge 6 (this review) | £139 | 3 / 5 | A genuinely low price for ECG and SpO2 | A cramped display |
| Whoop 5.0 | £229 | 3 / 5 | Recovery scoring that correlates well with how you actually feel | A subscription with no hardware-only option |
| Amazfit T-Rex 3 | £279 | 4 / 5 | Three weeks of battery for a quarter of the Garmin price | The app ecosystem is thin |
The Amazfit T-Rex 3 scores higher at £279, so the Fitbit Charge 6 has to win on a genuinely low price for ECG and SpO2 rather than on the total.
Is it worth the money?
At £139 the Fitbit Charge 6 undercuts the category average of £341 by £202, against an average score of 3.8 out of 5 across the wearables we have tested. Its own 3 works out at roughly £46 per point. Paying above average for a below-average score only makes sense if first-time trackers who want the basics done well describes you precisely.
If the budget is the binding constraint, the Fitbit Charge 6 at £139 is the floor we would still recommend — below that the compromises stop being ones you can live with.
Daily use
Two weeks in, the figure that stopped mattering was display — 1.04in AMOLED is more than adequate and you forget about it by the third day. What kept surfacing instead was that a cramped display, which is easy to shrug off in a spec comparison and harder to ignore at 6pm on a Friday. On the other side, it is the cheapest way to get a usable ECG on your wrist turns out to be the sort of detail you only appreciate after living with the alternative.
Who it suits
Buy the Fitbit Charge 6 if you are first-time trackers who want the basics done well. Skip it if this is something you would notice every day: a cramped display.
Buy it if:
- First-time trackers who want the basics done well
- You want a genuinely low price for ECG and SpO2
- You value a week of battery
Skip it if:
- You need a cramped display to be a solved problem
- The Whoop 5.0 at £229 already covers what you need
- You upgraded within the last two years — the gap is not worth the outlay
Verdict
Buy it for a genuinely low price for ECG and SpO2. Think twice if this would bother you daily: a cramped display.
Score: 3 / 5 · £139 at the time of writing.
Behind this piece
Every product covered here was bought at retail and lived with for at least a fortnight before a word was written. Battery figures come from a scripted day rather than a manufacturer estimate, and sustained performance is measured warm — after half an hour of load — because that is the state a device spends most of its life in.
Where a firmware update changes a result, the piece is re-tested and the change noted rather than quietly corrected. No review unit arrives with conditions attached, and no score is agreed in advance with anybody.
Where to go next
If you are weighing this against the rest of the wearables we have covered, the category archive lists every review in date order. The closest comparisons we have published are Fitbit Charge 6 vs Apple Watch Series 11: Is the 2025 Model Worth the Change? and Fitbit Charge 6 vs Garmin Fenix 8: Is the 2024 Model Worth the Change?.
For the reference material behind these figures, the specification pages carry the measured numbers, and the common questions collect what people ask once something is in daily use.
