Casio F-91W-1YEF review
The cheapest good watch there is: a lifetime of use for the price of a lunch.
- Skip it if
- You want something that feels solid
as of 6 Nov 2026, 14:25 GMT · Details
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Researched, not used. We haven't used this product. This review is built from the maker's details and what other buyers report.
What we like
- Alarm, hourly chime, stopwatch and backlight
- Battery rated at around seven years
- Very light resin case, easy to forget
Worth knowing
- Feels like a light plastic watch
- Only splash resistant
- Small buttons and short strap for larger wrists
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Our review
The F-91W is Casio's plain black digital, on sale since 1989 and one of the best-selling watches ever made. It gives you the time, a daily alarm, an hourly chime, a stopwatch and a backlight in a resin case that weighs almost nothing. It runs on a small battery that Casio rates at around seven years. The catch is that it feels like what it is, a light plastic watch, and it is only splash resistant.
What it is
The F-91W-1YEF is the black-resin version of Casio's most famous digital. The design has barely changed in decades, which is much of the appeal: a small rectangular case, a grey-on-pale LCD, and four buttons around the edge. It sits at the very bottom of Casio's range on price, below the retro metal-cased A-series and well below any G-Shock, yet it has a cult following that those watches do not.
The movement
Inside is a basic quartz digital module. Casio quotes accuracy of about 30 seconds a month either way, which is fine for a watch with no sweep hand to compare against. The battery is a standard coin cell and Casio gives a life of roughly seven years, though how long yours lasts depends on how often you use the alarm and light. When it dies you swap the cell yourself, or any watch shop will do it quickly. There is no solar charging and no radio sync, so you will need to nudge the time now and then.
On the wrist
The case is small by modern standards, a little over 33 mm across, and very thin and light. It is easy to forget it is there, which suits sleeping, running or gardening. The flip side is that the resin feels hollow, the buttons are small and slightly stiff, and the strap is a simple resin band with a plain buckle that fits slimmer wrists best. Larger wrists can run short of holes on the strap, so check the maker's strap length on the listing.
Water and everyday wear
The F-91W is only water resistant in the everyday sense. Treat it as fine for rain and hand washing, and take it off for swimming and showers. The front is resin rather than mineral or sapphire glass, so it scratches more easily than a pricier watch, although it is cheap enough that few owners mind. The backlight is a small light you press for a moment, and there is no lume on the display, so in the dark you need the button.
Against the alternatives
The closest rival in spirit is the Casio A158WEA-1EF, which has the same functions in a steel case and bracelet and feels more solid. The Casio G-Shock DW-5600E-1V is tougher and has a far better water rating, but is much bulkier. If you want an analogue watch with similar simplicity and low cost, the Casio MQ-24-7BLL is a light three-hander. For a first digital or a spare beach watch, the F-91W is hard to beat on value.
Who it's for, and who should skip it
It is for anyone who wants a dependable, lightweight timekeeper with a useful alarm and stopwatch and does not mind plastic. It makes a good spare, travel or gym watch. Skip it if you want something that feels solid or looks smart, if you need a proper swim-ready rating, or if you want automatic time setting. Its look is a deliberate retro one and may not suit smarter clothes.
A researched review, built from the maker's specs, manual and Amazon.co.uk listing; facts checked 6 Nov 2026.
Who shouldn't buy this
Don't buy it if you want something that feels solid: it's very light plastic.
Key specs
| Movement | digital |
| Calibre | Casio 593 |
| Case | 35.2 mm |
| Thickness | 8.5 mm |
| Lug width | 18 mm |
| Water resistance | — |
| Crystal | — |
| Strap | resin |
| Power reserve | — |
| Accuracy | ±30 s/month |
This is a Researched review: we haven't used this product. We check the maker's details against at least two independent sources, re-check the price where we can track it automatically, and say plainly who it isn't for. Commissions never change a rating.
If this isn’t the one
as of 6 Nov 2026, 14:25 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.
as of 6 Nov 2026, 14:25 GMT · Details
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.co.uk at the time of purchase will apply to the purchase of this product.