HP · RPN programmable · 1979–1983
HP-34C
The HP-34C shipped in late 1979, the same year as the HP-41C, and did two things no pocket calculator had done: it could solve f(x) = 0 at the press of a key, and it could integrate. HP Journal ran a feature on each. Both carried forward into the HP-15C, which replaced the 34C in 1982. Its memory flexes between 70 program lines with 21 registers and 210 lines with one, it has subroutines, flags and indirect addressing, and Continuous Memory keeps it all with the power off. HP's code name was Basil. It belongs to the Spice series, larger than a Woodstock, with a red LED display and a two-cell NiCd pack, and HP sold it until 1983.
Good forEngineeringCollecting
Spec at a glance
- Maker
- HP
- Type
- RPN programmable
- Launched
- 1979
- Made
- 1979–1983
- Entry
- RPN
- Display
- LED
- Programmable
- Yes
- Memory
- 70 program lines and 21 registers, convertible up to 210 lines and 1 register
- Built in
- SOLVE root finder and numerical integration, gamma function
- Display
- 10-digit red LED
- Power
- Two AA-size NiCd cells in a pack; use HP's B-suffix charger
- Series
- Spice (HP's Series E)
- Also listed as
- HP 34C, HP34C
- Typical eBay ask (Oct 15, 2026)
- $370–$380
Bench check
Power, memory, display and keys
- Battery and power
- A pack of two AA-size NiCd cells, about 3 hours of use per charge. HP's handbook says never to run it from the charger with the pack out, and to use the B-version charger, because the older A version can clear Continuous Memory when you plug it in. Collectors report Spice battery contacts breaking off and chargers with poor contacts.
- Memory
- Continuous Memory keeps programs, registers and the display format, but not the stack or the angle mode. Pr Error at switch-on means it was lost. HP notes a NiCd pack loses about 1 percent a day sitting idle.
- Display
- A 10-digit red LED behind a red cover. Collector Tony Thimet says the cover's upper corners tend to break off when it's dropped.
- Keys
- Three prefix keys. Later units had a metal keyboard and earlier ones plastic, and the boards changed from pressure-mounted to soldered in 1983.
- Original, reissue or clone
- It's a Spice, larger than a Woodstock, and there was never an HP-34E. Don't confuse it with the WP 34S, a modern open-source calculator. The serial starts with the year counted from 1960 and a country letter, S for Singapore.
Should come with it
- A working pack and HP's B-suffix charger
- The owner's handbook and applications book
Check the listing photos against this list, and ask the seller about anything you can’t see. A missing piece should come off the price.
What to check
Spice calculators are known for broken display-cover corners, broken battery contacts and poor charger contacts. Run it on the pack, never the charger alone.
- 01Display cover: Look at the red display cover's upper corners in the photos. Whole corners with no chips are what you want.
- 02Battery contacts: Ask for a photo with the pack out. Both contacts should be there and free of crust.
- 03Pack: Ask whether it runs from the pack alone. If it only works on the charger, plan on a new pack.
- 04Memory: Ask whether it switches on without Pr Error after a day off. A program that survives is what you want.
- 05SOLVE: Ask the seller to try the SOLVE example from the handbook. A root in a few seconds means the key logic works.
- 06Keys: Ask whether every key registers once per press. No dead or doubled keys is what you want.
New to old calculators? The condition checklist covers battery corrosion, displays, keys and card readers, and RPN in one hour gets you typing on an HP.
Buying guide
Which one to buy
§ Oct 15, 2026This is the only HP-34C for sale, at $380 delivered, so one ask isn't a market read. It's titled with a case, charger and battery but makes no test claim, and the photo shows the display off. Ask whether the charger is HP's B-version, since the older A version can clear Continuous Memory when you plug it in, and never run it from the charger with the pack out. Ask for a photo of the display showing all 8s, a look at the battery contacts and the corners of the red display cover, which tend to break, and a stored number recalled after switching off; Pr Error at switch-on means the memory was lost.
- Listed now
- 1
- For parts
- 0
- Typical ask
- $370–$380
- Full range
- $380–$380
Snapshot
For sale on eBay
1 of 1 listedChecked . Some may have sold.
Delivered prices include shipping as eBay quoted it to a US address on Oct 15, 2026. Many sellers charge by distance, so your total may differ. eBay shows yours before you pay.
UsedVintage Hewlett Packard HP34C Calculator Programmable With Case Charger Battery
$379.95delivered
$379.95 · free shipping
Buy It Now$379.95
Offers accepted
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Our take
Titled with case, charger and battery. No test claim; photo shows the display off.
Seller: phidas
100% positive
Prices change daily. The live eBay search shows everything listed now, including anything new since Oct 15, 2026.
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