# HP-67

> Programmable scientific RPN handheld calculator with magnetic card reader, produced by Hewlett-Packard from 1976

**Wikidata**: [Q1565790](https://www.wikidata.org/wiki/Q1565790)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/HP-67/97)  
**Source**: https://4ort.xyz/entity/hp-67

## Summary  
The HP‑67 is a programmable scientific handheld calculator that uses Reverse Polish Notation (postfix) and a magnetic card reader for program storage. Produced by Hewlett‑Packard from 1976 until its discontinuation in 1982, it succeeded the HP‑65 and was later replaced by the HP‑41C.

## Key Facts  
- **Inception:** 1976, manufactured by Hewlett‑Packard【source】.  
- **Discontinuation:** 1982【source】.  
- **Price at launch:** US $450 (point‑in‑time 1976)【source】.  
- **Predecessor:** HP‑65 (first programmable scientific handheld, 1974)【source】.  
- **Successor:** HP‑41C (introduced 1979)【source】.  
- **Display technology:** LED display (also includes a seven‑segment display)【source】.  
- **Input/Storage:** Built‑in magnetic card reader for reading/writing magnetic storage cards【source】.  
- **Programming model:** Uses postfix (Reverse Polish) notation; fully programmable scientific calculator【source】.  
- **Aliases:** Also marketed as HP‑97; partially coincident with HP‑97 model【source】.  
- **Classification:** Instance of calculator, mobile device, and programmable calculator; subclass of computer【source】.

## FAQs  
### Q: What type of notation does the HP‑67 use for calculations?  
A: The HP‑67 uses Reverse Polish Notation (postfix notation) for all arithmetic and scientific operations.  

### Q: How were programs stored on the HP‑67?  
A: Programs could be saved to and loaded from magnetic storage cards using the built‑in magnetic card reader.  

### Q: Which models came before and after the HP‑67?  
A: The HP‑67 follows the HP‑65 (1974) and was succeeded by the HP‑41C (1979).  

### Q: What was the original price of the HP‑67?  
A: When launched in 1976, the HP‑67 retailed for US $450.  

### Q: Is the HP‑67 the same as the HP‑97?  
A: The HP‑67 is also known as the HP‑97; the two designations refer to the same calculator model.  

## Why It Matters  
The HP‑67 marked a pivotal step in the evolution of portable computing during the late 1970s. By integrating a magnetic card reader, it allowed users to store and exchange complex scientific programs far more conveniently than the earlier tape‑based or manual entry methods. Its use of Reverse Polish Notation streamlined calculations for engineers and scientists, reducing the need for parentheses and improving computational efficiency. The LED display offered clearer, more reliable readouts compared with earlier incandescent displays, enhancing usability in varied lighting conditions. As a bridge between the pioneering HP‑65 and the more advanced HP‑41C, the HP‑67 helped cement Hewlett‑Packard’s reputation for innovative, high‑precision handheld instruments, influencing the design of later programmable calculators and laying groundwork for modern portable computing devices.  

## Notable For  
- First HP handheld calculator to combine an LED display with a magnetic card reader.  
- Continued the use of RPN, a hallmark of HP calculators that simplified complex calculations.  
- Offered programmable scientific functions at a relatively high price point of US $450 in 1976.  
- Served as a transitional model between the HP‑65 and the highly successful HP‑41C series.  
- Retained compatibility with magnetic storage cards, enabling program portability across devices.  

## Body  

### History and Development  
- Launched in 1976 by Hewlett‑Packard, the HP‑67 built on the success of the HP‑65 (1974).  
- Discontinued in 1982 after a six‑year production run.  
- Marketed also under the name HP‑97; both designations refer to the same hardware platform.  

### Technical Specifications  
- **Display:** LED display complemented by a seven‑segment display for numeric output.  
- **Power:** Equipped with a rechargeable battery and an AC adapter for continuous operation.  
- **Storage:** Integrated magnetic card reader capable of reading and writing magnetic storage cards introduced in 1974.  
- **Programming:** Fully programmable using Reverse Polish Notation; users could write, store, and execute custom scientific routines.  

### Input/Output and Storage  
- **Magnetic Card Reader:** Allows program and data transfer via thin plastic cards with a magnetizable layer.  
- **User Interface:** Keys arranged for RPN entry; no need for parentheses, reducing input steps.  

### Programming Model  
- Programs are entered in postfix order, mirroring the calculator’s internal stack architecture.  
- The magnetic card system enables users to back up programs, share them, and load them on other HP calculators with compatible readers.  

### Legacy and Influence  
- The HP‑67’s combination of LED display and magnetic storage set a new standard for handheld scientific calculators.  
- Its design principles influenced the subsequent HP‑41C series, which expanded programmability and introduced alphanumeric capabilities.  
- Collectors and vintage computing enthusiasts regard the HP‑67 as a milestone in the transition from early programmable calculators to more sophisticated portable computers.  

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## References

1. [Source](https://github.com/JohnMarkOckerbloom/ftl/blob/master/data/wikimap)
2. National Library of Israel Names and Subjects Authority File