400APD UNDERWOOD Electric Calculator

Review UNDERWOOD Vintage Electric Calculator Tested Working

The Underwood 400APD Electric Calculator is a versatile and reliable desktop calculating machine manufactured by Underwood-Baker Co. This calculator, which was introduced in the late 1960s, is a testament to the engineering prowess of the era and remains a sought-after item for collectors and enthusiasts.

The Underwood 400APD boasts a sleek and modern design, with its matte black finish adding an air of sophistication. Its compact size, at approximately 11 inches long, 8 inches wide, and 3 inches tall, makes it an ideal choice for home offices, classrooms, or any workspace where accurate and efficient calculation is a priority.

The calculator's operation is based on a series of electrically activated gears and relays, which enable it to perform the four basic arithmetic functions: addition, subtraction, multiplication, and division. The large, easy-to-read keys are clearly labeled, making it straightforward to perform even the most complex calculations.

One of the most distinctive features of the Underwood 400APD is its built-in paper tape, which records the calculations as they are performed. This feature not only offers an additional level of verification but also allows users to review their work, making it an invaluable tool for problem-solving and analysis.

The calculator is powered by a AC 120V, 60Hz power supply, which ensures a consistent and reliable power source. The power cord is generously long, allowing users to place the calculator at a comfortable working distance from an electrical outlet.

The Underwood 400APD Electric Calculator is not only a functional tool but also a piece of history. Its robust construction, combined with its innovative design, makes it a fascinating artifact of the technological advancements that shaped the latter half of the 20th century. Whether you're an avid collector, a history buff, or simply someone who appreciates fine engineering, the Underwood 400APD Electric Calculator is an essential addition to your collection.

The Underwood 400APD electric calculator is a vintage model that was popular during the mid-20th century. Here are some pros and cons to help you decide if buying this calculator is a good investment:

1. Historical Value: The Underwood 400APD is a piece of computing history. It is a collector's item and can be a conversation starter.

2. Reliability: Vintage calculators like the Underwood 400APD are known for their durability and reliability. They can handle complex calculations with ease and accuracy.

3. Manual Calculation: The Underwood 400APD does not require batteries or electricity to perform calculations. It uses a crank to add, subtract, multiply, and divide numbers. This can be a useful backup in case of power outages or when batteries are not available.

4. Tactile Feedback: The calculator provides a satisfying tactile feedback with each calculation, which can be enjoyable for some people.

1. Limited Functionality: The Underwood 400APD is a basic calculator and lacks the advanced features of modern calculators. It can only perform basic arithmetic operations.

2. Slow Calculation Speed: The calculator operates manually, which means it is much slower than modern calculators. It can be time-consuming to perform complex calculations.

3. Maintenance: Vintage calculators require regular maintenance to keep them in good working order. The mechanical parts can wear out over time and may need replacement.

4. Repair Costs: If the calculator breaks down, repair costs can be high due to the availability and cost of spare parts.

The Underwood 400APD electric calculator is a unique and interesting piece of computing history. It has some advantages over modern calculators, such as reliability and durability, but it also has some disadvantages, such as limited functionality and slow calculation speed. The decision to buy this calculator depends on your personal preferences and needs. If you are a collector or enjoy using vintage technology, then the Underwood 400APD could be a worthwhile investment. However, if you need a calculator for practical use and require advanced features, then a modern calculator may be a better choice.

If you are looking for a vintage calculator for collecting or as a conversation piece, then the Underwood 400APD is an excellent choice. However, if you need a calculator for practical use, then it is recommended that you consider a modern calculator with advanced features and faster calculation speed.

Details:

There are no chips or cracks in the plastic. The power cord and original cover are also included. 7206806 a roll of paper is also included. This has been tested and the calculator paper feed / roll works fine.

Its yellowed some with age, but aside from that, its in great overall shape. Vintage Underwood 400 apd electronic calculator working condition - tested adding machine / calculator printer.

specifications vintcalc:

• brand: Underwood
• mpn: 400apd
• model: Underwood 400apd
• part type: Calculator
• country of origin: Hong Kong
• vintage: Yes

offer vintcalc:

• in stock #: 1
• price: $23.50
• item condition: Used
• options: ship-to-home
• availability: in stock
• best offers: true
• started: january 26, 2026
• sold #: 9

general vintcalc:

• category: Electronics > Vintage Calculators

seller vintcalc:

• city: goleta, california
• # reviews: 73
• rating: 100.0%

returns vintcalc:

• time: 14 days
• method: money back
• policy: returns accepted
• paid by: buyer

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• credit card: visa
• wallet: paypal
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shipping vintcalc:

• service: usps ground advantage
• transit: 4-10 days
• type: fixed
• class: standard
• carrier: usps