Quick Answer
For ten dollars more the AE-1200WH adds 100 m of water resistance, world time across 31 zones, a ten-year battery and a full auto-calendar. What it costs you is size: 45 mm end to end and 12.5 mm tall against the F-91W's 38.2 and 8.5. If it fits your wrist, it is the better watch.
This is the clearest ten dollars in the Casio catalogue. Both are resin digitals with the same ±30 seconds a month, and both are cheap enough to treat as disposable. The difference is that one of them can go in the water and tell you the time in Tokyo.
Specification Comparison
Casio F-91W
4 categories won
Casio AE-1200WH
2 categories won
- Typical street price
- $30Winner
- $40
- Movement type
- QuartzEven
- QuartzEven
- Caliber
- Not published
- Not published
- Power reserve
- Battery, approximately 7 years on a CR2016 (Casio specification)
- Battery, approximately 10 years on a CR2025 (Casio specification)Winner
- Stated accuracy
- ±30 seconds per month (Casio specification)Even
- ±30 seconds per month (Casio specification)Even
- Case width
- 35.2 mm
- 42.1 mm
- Case thickness
- 8.5 mmWinner
- 12.5 mm
- Lug-to-lug
- 38.2 mmWinner
- 45 mm
- Crystal
- Resin glassEven
- Resin glassEven
- Water resistance
- Water Resistant (Casio publishes no depth rating)
- 100 m (328 ft)Winner
- Bracelet / strap
- Resin strap
- Resin strap
- Weight
- 21 gWinner
- 39 g
- Style
- Digital · Everyday
- Digital · Sport · Everyday
- Recommended wrist
- Small · Medium
- Medium · Large
- Selection Score
- Not published
- Not published
Selection Time Verdict
Choose the Casio F-91W
Choose the F-91W if the watch has to disappear. 21 g and 8.5 mm slide under any cuff, and nothing about it draws a second look — which for a second watch, a work watch or a child's watch is the entire specification.
Read the full reviewChoose the Casio AE-1200WH
Choose the AE-1200WH if you swim, travel, or want the most watch forty dollars can buy. World time covers 31 zones and 48 cities with four of them on screen at once, the calendar runs to 2099 unattended, and Casio rates the CR2025 for ten years — twice the F-91W's interval.
Read the full reviewOn specification this is not close: for ten dollars the AE-1200WH adds the one thing the F-91W genuinely lacks — a depth rating you can swim with — plus a complication that would cost four figures in a mechanical watch. The F-91W's answer is its size. At 45 mm end to end and 39 g the AE-1200WH is still light, but it is a watch you notice; the F-91W is not. Measure your wrist, then buy the AE-1200WH unless the answer is that it will not fit.
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Frequently Asked Questions
Can the AE-1200WH be worn swimming?
Yes. Casio rates it to 100 m, which covers swimming and snorkelling. The F-91W carries no depth rating at all — Casio publishes only the words 'water resistant' for it.
Is the AE-1200WH too big for a small wrist?
Check the span rather than the width: 45 mm end to end against 38.2 mm for the F-91W. It is light at 39 g, but on a wrist under about 16 cm it will read as a large watch.
How long do the batteries actually last?
Casio specifies approximately seven years on a CR2016 for the F-91W and approximately ten years on a CR2025 for the AE-1200WH. Heavy use of the backlight shortens both, but the interval is measured in years either way.
Updated September 9, 2026