HP · RPN programmable · 1977–1979
HP-29C
The HP-29C of 1977 was the last and most capable Woodstock, and its twin, the HP-19C, added a printer. It doubled the HP-25's program memory to 98 steps and gave you 30 storage registers, plus the things the 25 lacked: subroutines, labels, loop counters and indirect addressing. Continuous Memory came standard, so your programs and 16 of the registers survive switching off. Tony Thimet, who collects these, compares its feature set to the later HP-11C. BYTE ran a prime-number program for the 19C and 29C in 1980. It has the Woodstock's red LED display and two-cell NiCd pack, and HP sold it until 1979, when the LCD era began.
Good forCollecting
Spec at a glance
- Maker
- HP
- Type
- RPN programmable
- Launched
- 1977
- Made
- 1977–1979
- Entry
- RPN
- Display
- LED
- Programmable
- Yes
- Memory
- 98 program steps, 30 storage registers (16 kept with the power off)
- Programs
- Subroutines, labels, loop counters and indirect addressing
- Display
- 10-digit red LED
- Power
- HP 82019A pack of two NiCd cells
- Battery life
- Typically about 3 hours of use per charge (HP)
- Also listed as
- HP 29C, HP29C
- Typical eBay ask (Oct 15, 2026)
- $440–$450
Bench check
Power, memory, display and keys
- Battery and power
- The Woodstock 82019A pack and HP's 82026A or 82041A charger in the US. HP's service manual says connecting the charger with the batteries out could damage the calculator, and the battery must be in place for it to run. Collectors report the battery contacts breaking off.
- Memory
- Continuous Memory keeps your programs, the 16 primary registers, the display format and the X register. The other 14 registers and the rest of the stack are cleared. If memory was lost, the display shows Error when you switch on.
- Display
- A 10-digit red LED. A blinking decimal point warns that the pack is nearly flat.
- Keys
- The Woodstock keyboard with f and g prefix keys. Ask about any key that needs a hard press.
- Original, reissue or clone
- Continuous Memory is printed along the bottom of the faceplate. The HP-19C is the same calculator with a built-in printer. The serial starts with the year counted from 1960, and the letter gives the country: A for the USA, B for Brazil, S for Singapore.
Should come with it
- An 82019A pack and HP's charger
- The owner's handbook and soft case
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
Dead packs and broken battery contacts are the usual problems, and the charger can damage it with no pack fitted. An Error display at switch-on means the memory was lost.
- 01Battery contacts: Ask for a photo with the pack out. Both contacts should be there and free of crust.
- 02Pack: Ask whether it runs from the pack alone. If it only works on the charger, plan on a new pack.
- 03Memory: Ask the seller to store a number in R0, switch off and on, and recall it. The number should come back with no Error.
- 04Display: Ask for a photo of the display lit with 8s. All ten digits should glow evenly.
- 05Keys: Ask whether every key registers once per press. No dead or doubled keys is what you want.
- 06Charger: Ask whether it was tested with the pack in. Running it on the charger alone can damage it.
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-29C for sale, at $446 delivered, so one ask isn't a market read. It's titled not tested with no power supply, so you'd be paying a working price for an unknown. An original 82019A pack is almost certainly dead, the battery must be in place for it to run, and HP warns that a charger connected with no batteries in could damage it, so ask the seller to fit a charged pack and show the display with all 8s lit before you pay. Continuous Memory is the 29C's point, and the photo shows the script on the faceplate, so ask them to store a number, switch off and on, and recall it; Error at switch-on means the memory was lost.
- Listed now
- 1
- For parts
- 0
- Typical ask
- $440–$450
- Full range
- $446–$446
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.
For partsVintage HP-29C Programmable Calculator, Case, No Power Supply - Not Tested
$446.39delivered
$446.39 · free shipping
Buy It Now$446.39
Our take
Not tested, with no charger. Photo shows the case and what looks like the battery pack.
Seller: harper_collectibles1
99.7% positive
Prices change daily. The live eBay search shows everything listed now, including anything new since Oct 15, 2026.
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