Fitbit Band Size Chart for Every Model
Fitbit band sizing has two answers that get confused with each other: the length size, Small or Large, which is the wrist range the band wraps, and the attachment, the physical connector that clips the band to the tracker. Every current Fitbit ships with both S and L bands in the box, so "what size band do I need" usually means "which of the two boxed bands goes on my wrist", and that is answered by one circumference measurement. The chart below covers every model family still in common use, in inches and millimeters, straight from Fitbit's and Google's own documentation.
Fitbit band size chart: all models, S and L wrist ranges
Ranges are wrist circumference the band wraps. Sources per row are in the Sources section; where reputable sources disagree, both numbers are shown and flagged.
| Model family | Attachment | Small band fits | Large band fits |
|---|---|---|---|
| Sense 2 / Sense | Slide-and-lock, shared with Versa 3/4 | 5.5-7.1" / 140-180mm | 7.1-8.7" / 180-220mm |
| Versa 4 / Versa 3 | Slide-and-lock, shared with Sense/Sense 2 | 5.5-7.1" / 140-180mm | 7.1-8.7" / 180-220mm |
| Versa 2 / Versa Lite / Versa | Standard 22mm quick-release pins | 5.5-7.1" / 140-180mm | 7.1-8.7" / 180-220mm |
| Charge 6 / Charge 5 | Snap-in clip, shared between the two | 5.1-6.7" / 130-170mm | 6.7-8.3" / 170-210mm |
| Charge 4 / Charge 3 | Classic pin-and-tuck on tracker frame | 5.5-7.1" / 140-180mm | 7.1-8.7" / 180-220mm |
| Inspire 3 | Quick-release, specific to Inspire family | 5.5-7.5" / 140-180mm * | 6.3-8.7" / 180-220mm |
| Inspire 2 / Inspire HR / Inspire | Quick-release, specific to Inspire family | 5.5-7.1" / 140-180mm | 7.1-8.7" / 180-220mm |
| Luxe | Micro-latch, specific to Luxe | 5.5-7.1" / 140-180mm ** | 7.1-8.7" / 180-220mm |
| Ace 3 (kids) | Pin-and-tuck, Ace specific | One size: 4.6-6.6" / 116-168mm | |
| Fitbit Air | Hook-and-loop textile loop, 18mm wide | Textile one size: 5.1-8.3" / 130-210mm | Silicone S 5.1-6.9" / 130-175mm, L 6.5-8.3" / 165-210mm |
* Inspire 3's inches (5.1-7.5 / 6.3-8.7) and millimeters (140-180 / 180-220) come from the same Google Store spec sheet and do not convert into each other exactly; Google publishes both, so both are shown. Earlier Inspire generations use the plain 140-180 / 180-220mm ranges.
** Luxe's Small start point is the one outright divergence in Fitbit's own paperwork: the Fitbit Luxe user manual says 5.5-7.1" (140-180mm), while iMore's sizing table lists 5.3-7.1" and its Large as 7.1-9". The manual's numbers are the ones above; iMore's are the flagged alternative. Either way the boundary is the same 7.1 inches.
The Ace row is one size, not S/L: kids' trackers ship a single band. The Fitbit Air row is split by band material because Google sells it that way, a stretch textile loop in one size and a silicone band in S/L. Full Air detail two sections down.
For the watch-style families, there is a second "size" number: the band width in millimeters that a replacement band must be. That question, including the 22mm Versa 1/2 group and the 24mm Versa 3/4 and Sense group, has its own deep dive in the Fitbit Versa band size guide.
How to measure your wrist for a Fitbit band
All a Fitbit S/L decision needs is your wrist circumference where the tracker sits, roughly a finger's width above the wrist bone. Wrap a soft measuring tape (or a paper strip marked and laid on a ruler) snugly but not tight, and read the number in inches or millimeters. The full walkthrough, including the paper method that needs no tape at all, is in the wrist measuring guide and the no-tape method. Two Fitbit-specific notes from the official wear guidance: the tracker should not slide freely around the wrist, and for workouts it sits higher and slightly tighter, so if you sit near a boundary line the Large band's spare holes are the safer pick.
Small or Large: where each family's line sits
- Most families: 7.1 inches / 180mm. Sense, Versa, older Charge, Inspire, and Luxe all switch from Small to Large at 7.1". The ranges deliberately overlap at that point; both bands fasten there. At or just above the line, use the Large: its extra length lives in the keeper, and wrists swell in heat and during exercise.
- Charge 6 and Charge 5: 6.7 inches / 170mm. The newer Charge bands are shorter overall (Large tops out at 8.3" / 210mm), so the boundary moved down. Over 210mm there is no official XL; extended-length third-party Charge 6 bands are the documented answer.
- Fitbit Air silicone: your call, both ship. The textile loop is one size and self-sizing; the silicone S/L pair splits at about 6.5-6.9 inches where its ranges overlap.
- Ace: no choice at all. One size, 4.6-6.6 inches, and the sizing question for kids is whether the wrist is inside that window at all.
Attachment families: which bands interchange
Length sizing is only half the purchase; the connector decides whether a band physically mounts. Fitbit's lineup sorts into a handful of families:
- Slide-and-lock (Sense, Sense 2, Versa 3, Versa 4). One 24mm-class system across all four; bands interchange freely within the group per Fitbit's own manuals. Google's wear guidance notes you switch S/L by replacing only the bottom band.
- Standard 22mm quick-release (Versa, Versa Lite, Versa 2). The odd one out: ordinary 22mm watch bands with quick-release pins mount straight on, which opens the door to the whole standard strap market. See the Versa deep dive for the pin-length quirk.
- Snap-in clip (Charge 5, Charge 6). Shared between exactly those two. Nothing from older Charges or any watch fits.
- Classic frame bands (Charge 4, Charge 3, and earlier). Their own latch; Charge 3 and Charge 4 bands interchange with each other, not with Charge 5/6.
- Quick-release tracker bands (Inspire generations, Luxe). Slim model-specific mounts; an Inspire 3 band does not fit an Inspire 2 and nothing crosses to Luxe's micro-latch.
- Ace. Its own kids' band; nothing else in the line mounts.
So: Versa 3/4 and Sense owners share one pool, Versa 1/2 owners get the entire 22mm standard strap world, and everyone else buys within their model's family. No Fitbit accepts Apple Watch bands, and Galaxy Watch 20/22mm bands fit Fitbits only in the Versa 1/2 case where the attachment is a standard pin rather than anything proprietary; those systems are covered in the Apple and Galaxy Watch band guides, and Garmin's QuickFit systems in the Garmin band size guide. Amazfit's own 20mm/22mm quick-release split, and the T-Rex connector traps around it, are covered in the Amazfit band size chart.
Fitbit Air: sizing the screenless tracker
The Fitbit Air ships with a textile Performance Loop band (18mm wide, hook-and-loop closure) that fits 130-210mm (5.1-8.3") in its single size, per Google's official spec sheet, with Android Police's review independently confirming 130-210mm on the same band. The optional silicone Active Band comes in Small (130-175mm / 5.1-6.9") and Large (165-210mm / 6.5-8.3"), again matching between Google's specs and Android Police's spec table. Because the loop is hook-and-loop, it adjusts continuously across its range with no holes, so the S/L question only exists if you buy the silicone band separately.
Kids and the Ace: sizing the smallest wrists
The Ace 3 is a one-size band covering 4.6-6.6 inches (116-168mm), a figure Fitbit's own Ace 3 kids' sizing guide and iMore's table agree on. Practically that covers most wrists from about age 6 up; below 4.6 inches no official band is short enough, and above 6.6 inches a child is usually into Inspire territory (5.5" Small start), which is the natural next tracker. Fitbit's kids' guidance also allows wearing an Ace on a wrist it is slightly loose on and tightening it one notch, but a band riding around the wrist is both a lost-tracker risk and a heart-rate reading killer, so the window matters more than the tracker color does.
Related guides
The Versa and Sense families have their own deep dive in the Fitbit Versa band size guide: band width classes, the 22mm vs 24mm split, and the third-party band compatibility traps. The wider smartwatch picture is in the smartwatch sizing guide and its expanded edition, with per-family pages for the Apple Watch, Galaxy Watch, Garmin, and Fossil systems. For traditional watches, the watch band size chart covers lug widths, and small wrists get specific advice in smartwatches for small wrists.
Sources
- Sense 2 / Sense and Versa 4 / Versa 3 rows (S 5.5-7.1" / 140-180mm, L 7.1-8.7" / 180-220mm): Fitbit's official versa3_sense sizing guide PDF (fitbit.com) independently corroborated by the Fitbit Versa 4 and Versa 3 user manuals (m.media-amazon.com Versa 4 manual, manualsfact.com Versa 3 manual), and Google's support page "How to wear your Fitbit device" for the shared slide-and-lock system.
- Versa 2 / Versa Lite / Versa row: Fitbit's official versa sizing guide PDF for Versa Lite Edition (S 5.5-7.1", L 7.1-8.7") plus iMore's Fitbit wrist-sizing table (Versa 2 5.5-7.1 / 7.1-8.7). The 22mm quick-release attachment is documented in the sibling fitbit-versa-band-size page's sources (wizeband.com, fitstraps.co.uk).
- Charge 6 / Charge 5 row (S 5.1-6.7" / 130-170mm, L 6.7-8.3" / 170-210mm): Google Store official Fitbit Charge 6 tech specs at store.google.com, independently corroborated by astrastraps.com's Charge 6 band guide (which cites the Google Store) and imore.com's table (Charge 5 5.1-6.7 / 6.7-8.3). Snap-in attachment shared between Charge 5 and 6: watchband.direct compatibility guide plus astrastraps.com.
- Charge 4 / Charge 3 row (S 5.5-7.1", L 7.1-8.7"): the official Fitbit Charge 4 user manual (staticcs.fitbit.com and its Google-hosted copy) and imore.com's table (Charge 4 5.5-7.1 / 7.1-8.7), with heartratemonitorsusa.com and digitalcitizen.life retail/review listings independently repeating the same ranges.
- Inspire 3 row: Google Store official Fitbit Inspire 3 tech specs (S 5.1-7.5", L 6.3-8.7"; mm 140-180 / 180-220), corroborated on the mm side by Google Store's official Inspire 3 Classic Band accessory page (S 140-180mm, L 180-220mm). The inches-vs-mm divergence is disclosed in the chart footnote.
- Inspire 2 / Inspire HR / Inspire row: Fitbit's official inspire classic sizing guide PDF (S 5.5-7.1" / 140-180mm, L 7.1-8.7" / 180-220mm) plus imore.com's table (Inspire 2 5.5-7.1 / 7.1-8.7).
- Luxe row (S 5.5-7.1" / 140-180mm, L 7.1-8.7" / 180-220mm): the official Fitbit Luxe user manual (fitbit.com manual_luxe PDF), independently corroborated by watchband.direct's Luxe sizing guide (5.5-7.1 / 7.1-8.7). Divergence disclosed: imore.com lists Luxe S as 5.3-7.1" and L as 7.1-9".
- Ace 3 row (one size 4.6-6.6" / 116-168mm): Fitbit's official Ace 3 kids' sizing guide PDF, independently corroborated by imore.com's table (Ace 3 one size 4.6-6.6").
- Fitbit Air rows (textile one size 130-210mm; silicone S 130-175mm, L 165-210mm; 18mm band width): Google Store's official Fitbit Air tech specs at store.google.com, independently corroborated by Android Police's Fitbit Air review at androidpolice.com (130-210mm textile; 130-175 / 165-210mm silicone; 18mm wide) and androidcentral.com's review specs.
- Inspire 3 row (cross-check): Google Store official Fitbit Inspire 3 tech specs and Inspire 3 Classic Band accessory page, both at store.google.com; third-party confirmation of the 140-180 / 180-220mm pair in retailer listings (unicoshop.altervista.org) and fitstraps-style accessory guides.
- Additional model-by-model wrist range cross-checks: gadgetsandwearables.com and fitstraps.co.uk Fitbit sizing tables (generic 140-180 / 180-220mm baseline), manualsfact.com Versa 3 manual, heartratemonitorsusa.com and digitalcitizen.life Charge 4 listings, and thetechylife.com's Fitbit band size roundup.
- Wear and placement guidance (both bands in box, bottom-band-only S/L swap, no XL for current models): Google Health support "How to wear your Fitbit device" and imore.com's wrist-measuring guide.