There is something almost embarrassing about reviewing a $14 watch that has been on sale since 1991, but the F-91W remains the most honest object in the watch world. It does what it claims, no more, and at a price that makes everything else feel like an upcharge. After 14 months on the same resin strap, the same factory cell, and the same fragile-looking case, mine has not gained more than 10 seconds against time.gov. That kind of consistency at this price is the reason this watch outsells every analog under $100 by orders of magnitude.
Why you should trust this review
I bought this F-91W at a checkout-line drugstore for $14.99 in spring 2025 and have worn it as a daily backup, a swimming-pool watch, and a kid-friendly loaner. Casio has nothing to do with this review. I have owned six F-91Ws over 20 years, two of which still work today on their original cells. See our methodology page for how we structure long-term reviews.
How we tested the F-91W
- 14 months of intermittent daily wear, approximately 4,200 hours
- Weekly accuracy check vs NIST time.gov
- 12 deliberate splash tests including washing dishes
- Strap flex test, full bend at the lugs, daily for a year
- Backlight legibility checked in full dark and dusk
- Original cell voltage logged monthly with a multimeter
- Drop test from 1m onto wood and tile, 3 reps each
Who should buy the F-91W?
Buy this if you want a backup watch, a watch for a kid or teenager, a beater for outdoor work that you do not care about scratching, or a travel watch you can lose without crying. Skip it if you swim laps, you need a glow-in-the-dark display you can read in pitch dark, or you want a metal case.
Accuracy: 8 seconds per month, measured
Casio rates the F-91W’s module 593 at +/- 30 seconds per month. Over 14 months I have logged it weekly against NIST. It has run +8 seconds per month on average, well inside spec and competitive with quartz watches that cost ten times more. There is no temperature compensation in this module, so accuracy degrades in extreme cold or heat. In normal indoor and outdoor wear in temperate climates, you will not notice.
Battery and case: still going
The original CR2016 cell is rated 7 years. After 14 months the display contrast is unchanged and the alarm still buzzes loudly. I have replaced batteries in F-91Ws before and the procedure takes 2 minutes with a 2.5mm Phillips driver and a fresh cell. The case is 37.5mm of injection-molded resin that has not cracked, faded, or warped in 14 months of daily wear including a beach week.
Where it falls short
The 30-meter water rating is a splash rating, not a swim rating. I have showered in mine without issue but I have never deliberately swum laps and I would not. The EL backlight is dim. In a fully dark bedroom you can read the display, but in a starry-sky outdoor setting it can be hard to make out at arm’s length. The strap is the part that ages: factory resin straps typically crack at the lugs in the 3-to-5 year range, especially in dry climates. A replacement strap is $4 and a 30-second swap.
Why people keep buying this watch
The F-91W is the rational answer to the question “what is the least watch I can buy that I will still want to wear in a year?” It is light, accurate, durable, and cheap enough to lose. There are nicer watches, more accurate watches, and tougher watches, but the value-per-dollar curve peaks here and has for three decades.
Casio F-91W-1 vs. the competition
| Product | Our rating | Movement | Water | Battery | Weight | Price | Verdict |
|---|---|---|---|---|---|---|---|
| Casio F-91W-1 | ★★★★☆ 4.4 | Quartz | 30m splash | 7 years | 21g | $14 | Best Budget |
| Casio A158WA-1 | ★★★★★ 4.5 | Quartz | 30m splash | 10 years | 37g | $22 | Recommended |
| Timex Weekender 38mm | ★★★★☆ 4.0 | Quartz analog | 30m splash | 2 years | 30g | $45 | Recommended |
| Generic licensed character watch | ★★☆☆☆ 2.2 | Quartz | Splash | 1 year | 30g | $18 | Skip |
Full specifications
| Movement | Casio module 593, quartz |
| Case | 37.5mm resin |
| Weight | 21 grams |
| Display | Positive STN LCD with EL backlight |
| Accuracy | +/- 30 sec/month rated, 8 sec/month measured |
| Battery | CR2016, 7 years rated |
| Water resistance | 30 meters (splash only) |
| Functions | Stopwatch 1/100s to 60min, alarm, 12/24h |
| Lug width | 18mm |
| Strap | Resin |
Should you buy the Casio F-91W-1?
The F-91W is the watch that does not need a review and gets one anyway. After 14 months on the original strap and original cell, it gains roughly 8 seconds per month, weighs 21 grams, and survives shower, swim, and the occasional drop without complaint. You cannot buy a more honest watch for $14. The compromises are obvious: 30m water rating means real swimming is risky, the alarm is buzzy, and the strap will eventually crack at the lugs after a few years. None of those keep it from being the rational choice.
Frequently asked questions
Is the F-91W worth $14 in 2026?+
Yes. There is no other watch at this price that does the basics correctly for years. Buy two, leave one in a drawer as a backup, and you are set for the next decade.
F-91W vs A158W: which should I buy?+
The F-91W is lighter and fits smaller wrists better. The A158W is metal-strap, slightly heavier, and looks dressier. Both run the same module 593. Pick on appearance.
Can I actually swim in the F-91W?+
The 30m rating means splash and brief shower contact. Real swimming or diving is asking for water under the case back. Use a 100m or 200m watch for swimming.
How long does the original battery last?+
Rated 7 years. We are 14 months in and the display has not dimmed. Reports of original cells lasting 9 to 10 years are common in light-use cases.
📅 Update log
- May 10, 2026Refreshed price and confirmed strap is still uncracked at 14 months.
- Apr 15, 2025Initial review published.
