Calculating Devices

Overview One of the earliest and most important skills that humans developed was counting. As quantities increase and the need to compare and interpret these quantities also increases, a strictly mental (abstract) mathematical model is no longer useful. Calculating devices offer a physical representation of quantities, helping users visualize and record their calculations. The history of calculating devices is a long one with many important stages of development. Today, antiquated calculating devices are popular with collectors worldwide.

History of Calculating Devices >From counting on your fingers and toes, to the use of enormous mechanical computers, there is a wide variety of calculating devices. Even with the advent of powerful electronic calculators, some calculating devices, such as the slide rule and the abacus, are still used today. For a brief description of the most common mechanical calculating devices, read the three-part series entitled “A Brief History of Mechanical Calculators” by James Redin. Early numerical tools are just one part of an article about the development of computers found on this Web page. Here, you can read about a wide variety of calculating devices ranging from notched stones to slide rules.

Different Calculating Device Designs What are some of the different designs of calculating devices, and who invented them? What are the major classifications of calculating tools, and what did they look like? Answers to these questions, and others, can be found at Perhaps the best-known and oldest calculating device is the abacus. In the 1940’s, the abacus was pitted against one of the most advanced electric calculators of the day in a test of speed. The abacus won! Follow this link to read more about this interesting event. For a simulation of how a real abacus works click on this link or this link.

Resources for Collecting Calculating Devices Whether you are a serious collector of antique calculating devices, or you just want to find more details about them, online collector’s Web sites are a great resource. Visit any of the following Web pages for detailed information about calculating devices, their prices, availability, and history.

Additional Links Early mechanical computers were the most complex non-electronic calculation devices ever built. Considered by some to be an important ancestor of modern computers, the Analytical Engine--conceptualized and partially built by Charles Babbage--was a steam-powered, gear-driven computing machine. Read all about it at The history of mechanical computers is the topic discussed on this Web page and a detailed timeline of mechanical computers history can be found at this Web page. A general history of computers, including both electronic and mechanical ones, can be found at