Meet NumWorks, the Modern Graphing Calculator

Fans include high-school teachers and tinkerers, who say it's easier than most gadgets to repair

Numworks calculator Photo: NumWorks

Many high school students need to use a graphing calculator for math and science classes and for parts of the SAT and ACT—sure, a laptop would work, but they’re not allowed because teachers and testing companies are afraid of cheating. 

Most of the graphing calculators in students’ backpacks are made by Texas Instruments, and they look a lot like models going back to when these gadgets were introduced in the 1980s. But as the school year gains steam, NumWorks, a calculator startup launched a few years ago, is expanding on a cult following among high school teachers, along with a slice of tech innovators who say they like the company’s consumer-friendly approach to repairs and tinkering.

More on the Right To Repair

“The same calculator my sister used in the late ’90s is still pretty similar to what they use now in terms of its functionality,” says BJ Etzold, a math teacher at St. Mary’s Central High School in Bismarck, N.D. “Even the speed hasn’t gotten all that much better.”

Popular graphing calculators can have a steep learning curve, according to Etzold. As an example, he points out that Texas Instruments calculators have both a negative button and a subtraction button. “Really, that’s the same thing mathematically,” he says, but if students hit the wrong button they can get a confusing error message. NumWorks calculators have one button both for negative numbers and subtraction. 

Other school teachers I’ve talked to say they are impressed with the NumWorks’ speed and functionality when compared with other graphing calculators on the market. And some say it’s a welcome opening in what has been a near-monopoly over a required piece of technology for many high school students. 

“If you only have one place to get your calculator, there’s not a lot of space to innovate and try to change the game,” says Taylor Gibson, dean of mathematics at North Carolina School of Science and Mathematics, a public school in Durham that’s part of the state university system and accepts students from across the state. “Having someone else who has new ideas can make the whole calculator space better as a whole. I think everyone wins as a result.”

NumWorks founder Romain Goyet says he decided to create a new calculator in 2016, after stumbling across a TI-89 calculator similar to the one he’d used in high school a decade earlier. He wanted it to look more modern, and to be intuitive enough so that students wouldn’t need to consult a multi-hundred-page instruction manual. “Today’s kids should have something better,” he says.

Thin, Light, Speedy

The first thing I noticed when I got my NumWorks calculator in the mail was how feathery it was. It weighs 6 ounces and is less than ½-inch thick, making it thinner and lighter than other graphing calculators, and less clunky than my phone. The arrow keys on the left-hand side of the device feel familiar because they match the design and position of the navigation keys on every video game controller. The calculator isn’t cheap at about $100, but is still less expensive than TI’s popular TI-84+, which costs around $120. 

The NumWorks calculator seems to work much faster than the typical, bought-at-Staples high school graphing calculator—that’s something several teachers mentioned to me, as well. A teacher I consulted says that the online emulator, which they use for connecting to a screen while teaching in class, is intuitive and faster than what they’re used to from other manufacturers. The calculator lets you zoom in and out of a graph, and work in fractions or decimals. And, it has built-in applications for statistics that the teachers like. “I think it’s a nice intuitive interface to do data collection, data visualization, and data analysis,” Gibson says.

Like the TI-84 Plus CE and TI-Nspire CX II graphing calculators, the NumWorks includes a version of Python, the popular programming language. It lets you choose among a handful of preloaded scripts, or write your own. Like many tech products but few other calculators, it gets periodic updates with new features and bug fixes. You can update the calculator by plugging it into your computer and logging in to your account using a Google Chrome, Edge, or Chromium browser. (I had to use a USB-A to USB-C adapter for mine.)

Embracing Right to Repair

In some ways, NumWorks is a typical hardware startup—the company took a little-noticed product category where there wasn’t much competition and tried to reimagine it. But the company stands out from many tech companies, large and small, by offering schematics, firmware source code, and even 3D files to let you print replacement keys and other components. 

By contrast, people who buy everything from smartphones to cars to tractors often have trouble fixing or modifying their products because the manufacturers limit access to spare parts and diagrams. That can be frustrating; it can also send more broken devices into early retirement as e-waste. 

“If a consumer buys a product, they own it—and they should be able to exercise their full rights of ownership, including the right to repair it,” says Maureen Mahoney, senior policy analyst at Consumer Reports. “Too many companies are making it difficult for consumers to make their own choices when it comes to repair, and we applaud companies like NumWorks for making this repair information available.”

Members of Congress, the Federal Trade Commission, and state legislators are all looking at ways to address the right-to-repair issue.

NumWorks’ open approach has helped it build a following beyond the classroom, in the maker community. “Distributing the schematic for the NumWorks calculator makes the devices much more repairable, and it’s a wonderful reminder of the time of early home computers, when nearly every electronic device included a schematic for both repairing failures as well as for tinkerers to modify the systems,” says Trammell Hudson, a security researcher and dedicated tinkerer.

Hudson has never had to fix his NumWorks calculator (he has repaired other brands’ devices), but he is one of many users who swapped out the firmware the calculator comes with—an operating system called Epsilon—with a user-created version called Omega. It came with geek goodies including a periodic table of the elements and a mathematical notation called RPN, or reverse Polish notation, where users enter the numbers before the operations they want to use. (Instead of adding two plus two by entering “2 + 2,” you enter “2 2 +” to get the same answer.) This reduces the amount of buttons one has to press when calculating complex expressions. 

It used to be easy to download Omega, the third-party operating system, by connecting your calculator via a USB cable. You could just as easily revert to the main OS, Epsilon, by simply clicking on the reset button. But when I tried to load Omega, I received a warning telling me I was unable to do so. 

Goyet says the new version of NumWorks’ software includes some changes in response to testing regulations and requirements by academic exam boards, which are different in each country. For example, European testing boards require exam modes for calculators with a blinking LED light, and don’t want any unofficial software to be able to work with that exam mode. Another testing board required that the reset button on the back of the calculator bring it back to factory settings. And the license governing the newest version of the calculator software doesn’t allow users to redistribute it; Goyet says the change is designed to prevent cheating. 

Goyet says that it’s still possible for people to build alternative operating systems on the older, less restrictive version of NumWorks’ code—as long as it doesn’t work in exam mode. And the new version of NumWorks software allows custom applications, which the company plans to improve support for. But any modified OS will display a pop-up saying that the calculator’s not using the official NumWorks operating system and that a calculator crash or reset will require users to reinstall it.

Hudson says that extending or replacing the firmware in the device is also an important part of repairability and prolonging the lifetime of usability. “It’s regrettable, although understandable, that NumWorks has had to lock down the ability of users to do so in order to preserve their certifications,” he says. And he hopes that in the future NumWorks will be able to make hardware changes that will balance the needs of different countries’ exam requirements while still preserving the user’s freedom to hack on their own devices.

Even with the new restrictions, users can still tinker on their NumWorks calculator. Publishing schematics and 3D files means that they can not only fix broken calculators but also customize them. You can use a 3D printer to create new calculator covers that are thinner, are more colorful, or have a unique design. Goyet says hobbyists have created custom keyboard keys and custom-printed circuit boards. 

You can also take your calculator apart. One person got the calculator to power a small robot car it was connected to. “Because we had all the schematics available, he was able to solder it onto our PCB,” Goyet says. A PCB, or printed circuit board, is a rigid structure with electrical circuits made up of metal wires and other components.

Goyet also pointed me to a GitHub page where someone used a Raspberry Pi—a tiny and affordable computer often used to learn programming—as a desktop computer, and the calculator as a screen and keyboard. “There are all kinds of fun experiments you can do specifically because we’re publishing all the schematics.” 

Should You Buy One?

NumWorks calculators certainly have their benefits. They are easier and more intuitive to use than many other, more established graphing calculators. 

That said, before buying one for a student, it’s worth finding out whether the calculator is allowed in their classroom, and whether it’s permitted for state testing. NumWorks has a page on its website that allows you to click on your state on a map for a list of exams where the calculator can be used. Texas Instruments has a similar map that shows where you can use that company’s calculators for state testing.

Students who are technically inclined may benefit from the documentation, schematics, and 3D files, which could make projects easier. That might be a nice side benefit if they can also use the calculator in class, but it’s certainly not a necessity for creative tinkering—there are plenty of online tutorials on how to use a $35 Raspberry Pi and other gadgets to do all kinds of tinkering.

For makers and tinkerers who don’t need a graphing calculator for school, a NumWorks calculator might be fun to have, but it’s worth noting that there is also a large community of makers that hack on Texas Instrument calculators, and Hewlett-Packard and Casio devices have fans as well.

People seeking dedicated reverse Polish notation calculators for novelty or nostalgia often struggle trying to find Hewlett-Packard’s HP 48 series, a series of RPN calculators that was produced until 2003. RPN functionality is not currently available as an app on NumWorks, but you can use a free online emulator for Omega OS, which includes RPN functionality. (There are also replicas and apps such as PCalc and RPN Calculator 48.)

If you’re on the fence about whether to get a NumWorks calculator, you can test it out before buying it by downloading the free app on Android or iOS, or by checking out the free emulator on the website. 

Editor’s Note: This article has been updated to remove the suggestion that NumWorks calculators may not be used in certain high school exams in Tennessee. The state Department of Education confirms to CR that the calculators meet state requirements. This article was first published on October 21, 2021.


Headshot of Electronics freelance writer, Yael Grauer

Yael Grauer

I am an investigative tech reporter covering digital privacy and security. I'm the lead content creator of CR Security Planner, a free, easy-to-use guide to staying safer online. Prior to Consumer Reports, I covered surveillance, online privacy and security, data brokers, dark patterns, clandestine trackers, security vulnerabilities, VPNs, hacking, and digital freedom for Wired, Vice, The Intercept, Slate, Ars Technica, OneZero, Wirecutter, Business Insider, Popular Science, and other publications. Follow me on Twitter (@yaelwrites)