Photo: Uncommon Artifact
Sixteen rubber keys, an 8-digit calculator and a battery rated for five years: the CA-506 is the spreadsheet that learned to tell the time.
Verdict
| What it is | Casio Data Bank CA-506 — resin-cased calculator watch, black dial surround, on a resin strap |
| Price | Not stated |
| Availability | In Casio's current Data Bank / Vintage line (variant availability varies) |
| The angle | A working calculator that predates the phone in your pocket — and outlasts its battery by years. |
| Verdict | The functions read as a joke until a phone dies. Then the keypad is the only calculator on the wrist in the room. |
The story
The CA-506 puts the display on the top half of the case and a 16-key rubber keypad on the bottom half, and calls that a watch. The keypad drives an 8-digit calculator; the module also carries dual time, a 1/100-second stopwatch, a daily alarm, an hourly signal and a full auto-calendar programmed to 2099. The case is resin — 44.9 × 34.8 × 10.6mm — and the battery is a CR2016 rated at roughly five years. The face says what it is in three lines: WATER RESIST, ALARM CHRONO, WR.
Photographed on the wrist for the daily story series, showing 10:19 on a Thursday. The judgement is about design stasis: Casio's calculator format was settled decades ago and has never needed a redesign, only reissues. Everything a phone does better, it does at the cost of a charged battery and an unlocked screen. The CA-506 does arithmetic at the press of a rubber key, with gloves-adjacent fingers, for five years at a time.
Specs
| Reference | CA-506 (black resin variant, as photographed) |
| Collection | Data Bank |
| Movement | Digital quartz, ±15 seconds per month |
| Functions | 8-digit calculator, dual time, 1/100-second stopwatch, daily alarm, hourly time signal, full auto-calendar (to 2099) |
| Case | Resin, 44.9 × 34.8 × 10.6mm |
| Crystal | Resin glass |
| Strap | Resin (steel-bracelet variants also exist) |
| Water resistance | "Water Resistant" — maker's splash rating, not a depth rating |
| Battery | CR2016, approx. 5 years |
What to check before buying
- Press every key. The keypad is the watch. Aged rubber keys go unresponsive one at a time, and the failure is only visible in use.
- Check the variant suffix. CA-506 production spans resin-strap and steel-bracelet versions in several colours; the suffix after CA-506 is the variant, and prices differ.
- Ask when the battery was changed. Five years is the rating, not a promise; a dim display on a fresh battery is a different problem.
- Inspect the strap keepers and lug ends. Resin straps of this design crack at the keeper and the spring-bar holes first.
Want one?
- In the shop: browse current stock — one-off pieces, and they turn over fast.
- Hunting one? Join the Want List — tell us the maker and the budget; pieces like this surface in our trawl most weeks.
Related picks
- RZE UltraHex UTD-8000 — a digital watch built like a tool
- Seiko RC-4500 WristMac on ShopGoodwill — the wrist computer that flew, closed at $156
- Grand Seiko SBGX343 — the anti-magnetic quartz with two-colour lume
Photographed for the daily wrist-shot story series — not our stock, and not a sales listing. Disclosure
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