“If something cannot go on forever, it will stop.”

Economist Herb Stein’s quote ran through my head while I read The Hustle’s excellent analysis of the graphing calculator market. This cannot go on forever.

Every new school year, Twitter lights up with caregivers who can’t believe they have to buy their students a calculator that’s wildly underpowered and wildly overpriced relative to other consumer electronics.

tweet text: "Hello my 8th grade son is required to have a TI-84 for school but we just cannot afford one- do you have any programs you could recommend"

The Hustle describes Texas Instruments as having “a near-monopoly on graphing calculators for nearly three decades.” That means that some of the students who purchased TI calculators as college students are now purchasing calculators for their own kids that look, feel, act and (crucially) cost largely the same. Imagine they were purchasing their kid’s first car and the available cars all looked, felt, acted, and cost largely the same as their first car. This cannot go on forever.

As the chief academic officer at Desmos, a competitor of Texas Instruments calculators, I was already familiar with many of The Hustle’s findings. Even still, they illuminated two surprising elements of the Texas Instruments business model.

First, the profit margins.

One analyst placed the cost to produce a TI-84 Plus at around $15-20, meaning TI sells it for a profit margin of nearly 50% – far above the electronics industry’s average margin of 6.7%.

Second, the lobbying.

According to Open Secrets and ProPublica data, Texas Instruments paid lobbyists to hound the Department of Education every year from 2005 to 2009 – right around the time when mobile technology and apps were becoming more of a threat.

Obviously the profits and lobbying are interdependent. Rent-seeking occurs when companies invest profits not into product development but into manipulating regulatory environments to protect market share.

I’m not mad for the sake of Desmos here. What Texas Instruments is doing isn’t sustainable. Consumer tech is getting so good and cheap and our free alternative is getting used so widely that regulations and consumer demand are changing quickly.

Another source told The Hustle that graphing calculator sales have seen a 15% YoY decline in recent years – a trend that free alternatives like Desmos may be at least partially responsible for.

You’ll find our calculators embedded in over half of state-level end-of-course exams in the United States, along with the International Baccalaureate MYP exam, the digital SAT and the digital ACT.

I am mad for the sake of kids and families like this, though.

“It basically sucks,” says Marcus Grant, an 11th grader currently taking a pre-calculus course. “It was really expensive for my family. There are cheaper alternatives available, but my teacher makes [the TI calculator] mandatory and there’s no other option.”

Teachers: it was one thing to require plastic graphing calculators calculators when better and cheaper alternatives weren’t available. But it should offend your conscience to see a private company suck 50% profit margins out of the pockets of struggling families for a product that is, by objective measurements, inferior to and more expensive than its competitors.

BTW. This is a Twitter-thread-turned-blog-post. If you want to know how teachers justified recommending plastic graphing calculators, you can read my mentions.

I'm Dan and this is my blog. I'm a former high school math teacher and current head of teaching at Desmos. He / him. More here.


  1. I think the primary justification(s) for continued classroom use seems to be:
    1. The overpriced, dedicated devices are the only devices allowed on standardized tests like the SAT, ACT and AP exams.
    2. The calculators are unintuitive and take a significant investment of time to develop fluency. The button pushes involved in finding zeroes, finding the intersections of curves or plotting data require regular repetition to become intuitive enough to be useful in high stress, timed environments. Doing a couple hours of review before a crucial exam does not put students in optimal shape to make effective use of the tools.
    3. The dedicated devices do not come with tools like photomath and snapchat which makes quickly graded summative assessment very difficult.

    I think these are all fair justifications given the reality of life as a math/science teacher. I think there are solutions to all three of these problems and I think they will significantly increase equity in the classroom. I love that you are working to interrupt this monopoly at Desmos and I’m glad to hear that you have had so much adoption on state tests and the SAT. Are you (or the College Board) also working on ways to provide access to the locked down and slightly simplified version of Desmos for classroom exams? Do you have pilots at schools where classrooms are using Desmos for the routine administration of summative assessments?

    • I realized my third point is hard to follow. What I mean is that the dedicated devices like the TI are designed to prevent some forms of cheating and that it is hard to give students access to Desmos in the classroom in a way that does not also allow cheating.

    • Hi Eric, I followed your third point but I’m still working on your second. Is your thought here that teachers have invested so much time helping students learn the keystrokes that they’re loathe to throw away that sunk cost?

      Are you (or the College Board) also working on ways to provide access to the locked down and slightly simplified version of Desmos for classroom exams? Do you have pilots at schools where classrooms are using Desmos for the routine administration of summative assessments?

      Hard at work here!

  2. Virgil Fredenberg

    October 14, 2019 - 4:03 pm -

    It surprises me that we are still discussing this. Twenty years ago, at least, I brought up the question of what the calculator people were going to do once more people had access to computers at a national conference. They had no real answer, but acknowledged that calculators would never have the versatility of tablets and pcs. Even at the college level, calculators rule the classroom. And I have a box of obsolete calculators myself. I have my students use Desmos. Of course my tests involve explaining the graph, not creating the graph. I find their explanations tell me more about their understanding, than pushing the right buttons does. We need to move into the new century.

    • I missed that you responded to me. I’ll try to clarify my second point.

      I am not talking about a sunk cost that teachers are loath to give up on. Instead, I am positing that many teachers would be very willing to give up the TI calculators if they thought it was in the best interest of their students but, in my experience, teachers are almost always realists by requirement of the job.

      Teachers are not convinced that moving away from TI’s is in the best interest of their students because of things like the SAT. They know that students who are skilled with the calculator will have an advantage on the SAT. But they also know that using the TI efficiently requires a substantial investment of time and can only really be achieved with fairly regular use. So teachers ask students to use the calculator. Test-mode (which is AWESOME by the way) and making continued inroads with test makers will answer the empirical question. If I was in the classroom, I’d be very tempted to completely dump graphing calculators and to switch to Desmos with test-mode.

  3. While I don’t require a graphing calculator for my classes, I do suggest one. I’m certainly sympathetic to families for whom it’s a burden, and also suggest that you can do fine with a 4-function calculator.

    The one thing that the Texas Instruments calculators provide that I haven’t found a good replacement for is the TI-BASIC programming environment. The built in programming system is *such* a good introduction to programming that it almost justifies the cost of the physical device. It’s compact and discoverable in a way that programming environments on today’s computers aren’t. I’d dearly love Desmos to incorporate a TI-BASIC environment into their graphing calculator.

    • Oh wow yeah I loved that programming environment 20 years ago.

      (I’m not really sure why a scripting environment like Python wouldn’t suffice, though.)

    • Our school is philosophically opposed to screens in front of students (especially screens connected to the internet), so we only have one small set of Raspberry Pis that I use to teach computer science. I originally tried to introduce kids via Python on their laptops, but it’s much harder to do in a classroom setting without ironclad configuration control over the machines and environments. Fun times when half the kids have Python 3, half 2.7, half Windows, half OS X, and some have a borked install of Python 2.7 *and* 3 that sometimes works and sometimes doesn’t. You ask kids to install a nice editor and find out that half of them don’t have admin privs on their machines. Every minute I’m fighting that I’m not teaching.

      I do break our class set of Pis out in upper level math classes to do things like Gauss Jordan elimination in Python. I think that people who are used to programming have a hard time perceiving how intimidating and difficult programming is to total novices.

      The barriers to access even of a Python scripting environment as compared to TI-BASIC are huge.

      The python documentation is written for experienced programmers, so the commands in Python aren’t as discoverable as the TI-BASIC commands, which are all happily listed in menus on the device itself.

      Even the TI REPL loop is tighter than Pythons. Forget a colon at the end of a conditional, and the error you get is confusing. Whatever bad thing you do in a TI program, it just takes you to the line that is bad.

      Beyond that, the syntax of BASIC is so compact and Python’s handling of math is so counter-intuitive. You don’t run into the same sort of actual computer science problems in Basic that you do with Python. Explaining to a classroom of children that 3/4 == 0, but that 3/4. == 0.75 because type systems is not a good use of (math) class time.

      This is one I’ve ground my teeth on for the past five years, and nothing is better than TI-BASIC yet. I wish something were so we could ditch these expensive monstrosities. If there were and exact emulator (including a push-button editor) of TI-BASIC in the Desmos website, we’d be one step closer to ditching the calculators.

  4. The Hustle article is great! I too was shocked when I entered my teacher training program 6 years after graduating high school, over which time my phone had metamorphosed from a flip phone to an iPhone that could play music, give me maps and directions, browse the internet, etc. while the graphing calculator stayed exactly the same. And did far less than my phone.

    Featured Comment

    However, I’m not sure that Dan, CAO of Desmos, is really the right person to make this point. Desmos is a for-profit venture capital funded startup. I can only assume that their goal is to take over and monopolize the same market as TI (or at least this must be what they argued to their investors). While they will probably remain free to students, they will charge testing companies who in turn charge school districts for their products. I would like more detail on how Desmos is not exploiting the exact same market as TI. Perhaps the money is not coming directly out of the pockets of parents on back-to-school shopping night, but effectively the cost is being bundled into their taxes or as a reduction in other school services to pay the cost of the exams, online textbooks, and other products that use Desmos.
    • Yeah, fair point. I’m definitely not going to fight you too hard on my conflict of interest here. (Which I disclosed in the post!)

      I only want to point out that dismantling TI’s monopoly doesn’t mean Desmos inherits it.

      We have warmed states and other groups up to the idea of a web-based calculator embedded on their state exams, which only makes it easier for other web-based calculators to compete in the same space.

      And I think your analysis of the economics here is largely right. Desmos doesn’t charge students or families but it does charge people who charge students and families, even if indirectly through school taxes.

      But I’ve gotta point out quickly that we aren’t inheriting TI’s monopoly and we aren’t inheriting TI’s per-student prices. A TI-84 costs > $100 per student. Without undermining our business development team too much, I’ll say that our per-student costs are just a sliver of TI’s.

  5. I agree with others that requiring expensive calculators could be a burden to some families. Just like what Eric mentioned, just practicing how to use calculator functions before test will not benefit the students. Schools could provide graphing calculators for testings, but without the repeated practice of using graphing calculators for them use without thinking which button is for which during tests, students won’t find it beneficial to use. I know one alternative way to implement graphing calculators in class is using Desmos, but not all students will have access to Desmos because they need a computer/phone/laptop/iPad or other electronic devices in addition to internet service. Also, students won’t even be allowed to use these devices when taking high stake tests. Access to technology is a big deal for some families. Teachers, districts, states and federal need to consider ways to help all students be equable.

  6. Steve Geisthardt

    October 16, 2019 - 2:58 pm -

    I’m surprised no one has mentioned Casios yet. They’re half (or less) the cost of a TI, and I haven’t encountered a thing one can do that the other cannot (and many things the Casio seems to do with fewer keystrokes). I teach both AP Stats and AP Calc, so it’s not like there are huge portions of the US HS math curriculum I’m skipping. I’m sure there are some examples out there, but nothing that I do in class needs one or the other. The only thing I can think of is that your teacher prefers the TI, as they know how to use it, and the handouts are written with instructions for the TI. I suppose this may be an actual issue in a large department, but I teach most of my students for their last 2-3 years in HS math, so I’ve started recommending a Casio over a TI. I still don’t have all that many using one, most students get one from an older sibling, or had one passed down from whatever (so that’s the advantage they have over much of today’s technology, they will still be working in 20 years), so I have to implement “seating chart by calculator type” a little bit, but it works fine for me.

    As for the larger picture, yeah, it’s obviously standardized tests. Not so much the ACT/SAT, as a graphing calculator really doesn’t help that much over a scientific (I looked at the practice questions on the ACT website, and only saw one question where a graphing calculator was the easiest way to solve. Sure, there were another three or so where it was a possible way to solve, but if you knew enough to solve those with a graphing calculator, you probably knew enough to solve them without one as well.), but the AP tests, which absolutely require one. It killed me last year to enforce a graphing calculator instead of Desmos on my AP Calc class, as they were struggling with both calculus and the use of a graphing calculator at the same time. But if the goal is to get them ready to take the AP test, then they need to learn to use a graphing calculator to be ready for that test, which is not a thing that can be taught in a week (Dan, I think that was Eric’s second point, if you want them to learn to use a graphing calculator well enough for it to be useful on a test, that level of fluency with the calculator cannot be taught in a week, you need to be using it all year long).

  7. I used a slide rule in high school. At that time the argument was that Pickett was cornering the school market. They made the best cheap slide rules. In 1974 or so TI came out with an affordable scientific calculator. The slide rule and Pickett died almost over night. I have not seen the same thing happen with the graphing calculator. Laptops and software have not killed the TI because it seems to be the best tool for the job. Cheaper than a laptop, smaller than a laptop, and tailored for the task even if some of the key pressing is a pain. The limitations the TI has (no internet for instance) fit the classroom perfectly. Can you imagine the issues if there was a phone app that purported to replace the TI? The concept of “on task” would be a joke. The fact that TI has a virtual monopoly on the market is bad. The fact that math teachers only have to deal with one platform is great. In my senior stats class I allow TIs or Excel or Google Sheets or whatever they want to use. It has greatly increased my workload and the amount of time I have to do a show-and-tell of how to use tech in the class. When I was TI only life was easy. But I did not require kids to buy them. I had loaners bought by the school.

    My objection to the TI is the simple fact that outside the school environment they are non-existent. Nobody that I know of that uses mathematics on the job (other than teachers) has a TI on their desk. (I know an engineer that has a slide rule on his desk but he is older than dirt. I think he has it just to freak out his younger colleagues.) It kids use nothing but the TI then they are being shorted.

  8. I’ve LIVED your point, Dan! For over 20 years, I developed inks for ink jet printers (another high-margin business) as a chemical engineer for Dupont. People felt secure in their job. They said that the paperless office would probably come sometime after the paperless bathroom! And then smartphones arrived, people started to realize that there was no longer the need to print as much as they used to, and our sales flattened so much that our group of scientists was literally decimated (yes 1/10). I was not unhappy when they finally let me go! I think the progression of technology and science is the BEST reason to acquire or loose your job. No one should want to work in a job making buggy whips. If you fight the winds of change, your hat will eventually blow off, and you just might loose your shirt too.

    And the happy ending to the story is that, like you, I have now joined the edTech field and have created a new tool that allows blind students to perform arbitrarily complex algebraic manipulations – a much higher calling than selling buggy whips.

    BTW, I see that Desmos now offers UEB and Nemeth Braille output for its calculator – very cool! Also love the slide-whistle feature.

    “You can get me to do algebra. You can even get me to do calculus. But graphing is where I draw the line!” – Wish I knew who said this!

  9. Leigh Ann Mahaffie

    October 29, 2019 - 2:29 pm -

    I am struggling with this! I have opted not to put out my class set of TIs this school year, and let kids use their phones for calculator use. I spend a significant amount of time saying “if you aren’t using the calc app, put your phone away”. Even my most responsible students feel the tug of just checking their Snapchat, or their messages, or other apps. As I walk around, I am spending more time policing the phones, than I am checking their understanding. The TIs are looking better and better, daily. I can say “phones away” and not have to worry whether they are on-task.

  10. Malini Dasgupta

    October 29, 2019 - 7:23 pm -

    Schools should be buying classroom sets of whatever Texas Instrument calculators the teachers are requiring. After all, if the main reason we still have the TI’s is for standardized testing, which is something students are being required to do by the state, then it makes sense for public schools to provide these calculators free of cost to students. I also think teaching students how to use a TI calculator is not as hard as everyone seems to think it is. Dedicating a few lessons to modeling how to use them, and then providing students with some opportunities to practice with them in class on their own should suffice for the purposes of using them on standardized tests. As someone who took the ACT and AP math exams somewhat recently, I remember these standardized tests as being largely focused on conceptual and procedural understanding, requiring only minimal calculator use. The rest of the time (i.e. whenever the students are not practicing for a standardized test), students can use free-to-the-user alternatives like Desmos or SageMath, especially at home.