Quick Verdict
This is the F-91W with its one real flaw fixed. Casio gives both watches the same module, the same ±30 seconds a month, the same seven-year battery and the same 21 grams — but where the F-91W lights one corner of its display with an LED, the F-105W has an electro-luminescent panel behind the whole thing. That is what ILLUMINATOR on the dial means, and at the same $29.95 it is the more useful of the two. What you still do not get is a depth rating.
At a Glance
- Typical street price
- $30
- Movement type
- Quartz
- Power reserve
- Battery, approximately 7 years on a CR2016 (Casio specification)
- Case width
- 35.4 mm
- Lug-to-lug
- 39 mm
- Crystal
- Resin glass
- Water resistance
- Water Resistant (Casio publishes no depth rating)
Design
A 39 × 35.4 mm resin case, 9.6 mm thick, in the shape Casio has been making since the 1980s. The blue ring printed around the display is the only concession to decoration and it is the reason Casio's own page calls this a black and blue watch. Next to the F-91W it is fractionally longer, fractionally wider and 1.1 mm thicker — the extra millimetre is the EL panel, and it is a fair trade.
Movement
A Casio digital quartz module specified at ±30 seconds a month, running from a CR2016 that Casio rates for approximately seven years. There is nothing to wind, nothing to service and nothing to set beyond the initial time: the auto-calendar handles February on its own.
Build Quality
Resin case, resin bezel, resin glass and a moulded resin strap. The glass is the compromise, exactly as it is on the F-91W: it will collect scratches that a mineral crystal would not. Everything else is built to be ignored, which at this price is the point.
Dial
A grey LCD behind a black printed face, with CASIO and ALARM CHRONO across the top, ILLUMINATOR in the blue band above the display and WATER RESIST below it. Daylight legibility is excellent. In the dark the EL backlight glows blue-green across the entire display rather than bleeding from one corner, which is the single clearest reason to choose this over its more famous sibling.
Bracelet & Strap
The resin strap is moulded into the case, so there is no lug width and no possibility of a strap swap. That is not a shortcut; it is what keeps the watch at 21 grams and lets Casio seal it without a caseback gasket to maintain.
Comfort & Wearability
21 grams, the same figure Casio publishes for the F-91W, in a case 9.6 mm thick. It goes under a cuff without being noticed and it stays there.
Accuracy
Casio specifies ±30 seconds per month — about a second a day, held without winding, wearing or attention. Every mechanical watch in this catalogue is an order of magnitude worse and costs at least five times as much.
What we like
What we like
- An EL backlight that lights the entire display evenly, which is the one thing the F-91W gets wrong
- 21 g on the wrist — Casio specifies the same weight as the F-91W despite the larger case
- Seven years on one CR2016, so there is nothing to maintain
- ±30 seconds a month, published by Casio rather than estimated
- 1/100-second stopwatch with split timing and 1st-2nd place, a daily alarm and an auto-calendar
What we don't like
- Casio publishes no depth rating — only 'water resistant', which means splashes and rain
- Resin glass scratches where mineral would not
- The strap is moulded into the case, so there is no strap swap and no lug width
- 1.1 mm thicker than the F-91W, which is the price of the EL panel
Who Should Buy It?
Anyone who wanted an F-91W but has ever tried to read one in the dark. Also anyone who needs a watch they can genuinely stop caring about: a second watch, a work watch, a travel watch, a watch for a child.
Who Should Skip It?
Skip it if you swim. Casio publishes no depth rating for this reference — only the words 'water resistant' — and in Casio's own scale that means rain and splashes. The AE-1200WH is rated to 100 m and sits ten dollars higher in this same catalogue.
Best Alternatives
Three watches worth weighing up before you commit.
How It Compares
Casio F-105W
0 categories won
Casio F-91W
2 categories won
- Typical street price
- $30Even
- $30Even
- Movement type
- Quartz
- Quartz
- Caliber
- Not published
- Not published
- Power reserve
- Battery, approximately 7 years on a CR2016 (Casio specification)
- Battery, approximately 7 years on a CR2016 (Casio specification)
- Stated accuracy
- ±30 seconds per month (Casio specification)
- ±30 seconds per month (Casio specification)
- Case width
- 35.4 mm
- 35.2 mm
- Case thickness
- 9.6 mm
- 8.5 mmWinner
- Lug-to-lug
- 39 mm
- 38.2 mmWinner
- Crystal
- Resin glass
- Resin glass
- Water resistance
- Water Resistant (Casio publishes no depth rating)
- Water Resistant (Casio publishes no depth rating)
- Bracelet / strap
- Resin strap
- Resin strap
- Weight
- 21 gEven
- 21 gEven
- Style
- Digital · Everyday
- Digital · Everyday
- Recommended wrist
- Small · Medium
- Small · Medium
- Selection Score
- Not published
- Not published
Final Verdict
At $29.95 the question is not whether this watch is good but whether you would rather have the F-91W. On Casio's own published figures the F-105W matches it everywhere and beats it on the light, for the same money and 1.1 mm of thickness. Unless you specifically want the smaller, more iconic case, this is the better buy.
Specifications
- Brand
- Casio
- Model
- F-105W
- Reference
- F-105W-1A
- Collection
- Not published
- Typical street price
- $30
- MSRP
- $30
- Movement type
- Quartz
- Movement
- Casio digital quartz module
- Caliber
- Not published
- Power reserve
- Battery, approximately 7 years on a CR2016 (Casio specification)
- Stated accuracy
- ±30 seconds per month (Casio specification)
- Balance spring
- Not published
- Case width
- 35.4 mm
- Case thickness
- 9.6 mm
- Lug-to-lug
- 39 mm
- Lug width
- Not published
- Weight
- 21 g
- Case material
- Resin
- Crystal
- Resin glass
- Water resistance
- Water Resistant (Casio publishes no depth rating)
- Dial colours
- Black
- Bracelet / strap
- Resin strap
- Bracelet material
- Resin
- Clasp
- Not published
- Date
- Yes
- GMT
- No
- Chronograph
- Yes
- Style
- Digital · Everyday
- Recommended wrist
- Small · Medium
- Country of origin
- Japan
- Released
- Not published
- Selection Score
- Not published
Score Breakdown
Where to Buy
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Not published
Frequently Asked Questions
What is the difference between the Casio F-105W and the F-91W?
The light. Both run the same module at ±30 seconds a month, both weigh 21 grams and both cost $29.95, but the F-91W uses an LED that lights one corner of the display while the F-105W has an electro-luminescent backlight behind the whole display. The F-105W's case is also marginally larger and 1.1 mm thicker to fit the panel.
Can the Casio F-105W get wet?
Casio rates it as 'water resistant' without publishing a depth, which in Casio's own scale means rain and splashes rather than swimming. If you want to swim in a cheap Casio digital, the AE-1200WH is rated to 100 m.
How long does the F-105W battery last?
Casio specifies approximately seven years from one CR2016. Regular use of the backlight shortens that — an EL panel draws more than an LED — but it is still measured in years.