Old engineering coursework, a Khan Academy video, or just curious? This matches the real TI-85.
A free TI-85 calculator that runs in your browser. It works differently than the TI-84 you might be used to, and we explain exactly how before you touch a single key.
This runs our TI-84 Plus CE calculator engine, which covers everything the TI-85 does and more.
What is the TI-85, really
If you're not sure why this one looks different from the calculator your friends have, here's the short version.
The TI-85 came out in 1992 as Texas Instruments' second graphing calculator, built specifically for engineering and calculus students rather than general high school math. It was eventually replaced by the TI-86, and Texas Instruments stopped making it after that. You can read more of its history on Wikipedia's TI-85 page.
Most people land on this page one of three ways: they found an old TI-85 and want to know if it still works for their class, they're following a course or video that uses one, or they're just curious how an older engineering calculator worked. If you're actually choosing between calculator models to buy today, our TI-84 model comparison is the better place to start.
The feature that made it famous
Shortly after the TI-85 was released, people figured out something Texas Instruments never intended. By studying how the calculator's memory backups worked, enthusiasts found that a specially placed string could trick the calculator into running actual assembly language code instead of just TI-BASIC.
That mattered because assembly programs ran much faster and used memory far more efficiently. It made the TI-85 the first TI graphing calculator that could run assembly programs, years before Texas Instruments officially added that capability to the TI-83 and TI-86. It's also how early fan-made games like Tetris and Boulder Dash ended up running on it.
If you've ever wondered why the TI-85 has such a dedicated hobbyist following even decades later, this is why.
What you can actually do with it
Graphing
Function, parametric, and polar graphing, with the ability to work with up to 99 user-defined functions at once.
Calculus tools
Numerical derivatives and integrals, built for the engineering and calculus courses it was originally designed for.
Statistics
Regression, standard deviation, and the other core statistics functions you'd expect from a calculator this capable.
Matrices
Matrix math for linear algebra work, a big part of why it was popular in engineering programs.
Programming
Runs TI-BASIC, and with the assembly workaround described above, a lot more.
Split screen
View a graph next to its table, or an equation next to its graph, at the same time.
How the TI-85 is actually different to use
This is the part that trips people up if they've only ever used a TI-83 or TI-84.
Newer calculators like the TI-84 have separate, permanently labeled buttons for things like Y=, GRAPH, and WINDOW. The TI-85 doesn't work that way. Instead, it has five unlabeled keys, F1 F2 F3 F4 F5, positioned right under the screen.
Whatever menu you're in, the calculator shows a row of options along the bottom edge of the screen, and each option lines up with the F key directly beneath it. Press that key, and you select that option. The available options change constantly depending on what you're doing, which is what makes the TI-85 feel more complex at first than a TI-84.
The good news: once this clicks, it's not actually harder, just different. If you get lost in a menu, the EXIT key backs you out one step at a time.
Is the TI-85 allowed on the SAT or ACT? It isn't banned outright since it has no computer algebra system, unlike calculators such as the TI-89 or TI-Nspire CAS. But in practice, it's been out of production for decades, so it's not a calculator anyone realistically brings to a test today. If you're prepping for a standardized test, use a current TI-84 Plus instead.
Check the official ACT calculator policy for the current rules before test day.
TI-85 vs TI-84: which should you actually use
If you're picking a calculator to buy today, get the TI-84 Plus. It uses simpler, fixed buttons instead of context-changing soft keys, it's still updated and sold new, and it's the one your school almost certainly expects. The TI-85 is worth using if you already have one, you're following older course material built around it, or you're just curious how it works. See the full TI-84 model comparison if you're deciding what to buy.
What calculator does Sal Khan use?
If you've watched older Khan Academy math videos and noticed a calculator that doesn't look like your TI-84, that's likely a TI-85. It's one of the more specific reasons people search for this calculator today, whether to follow along with an older video series or just out of curiosity about the tool on screen. This simulator uses the same menu system, so you can follow along step for step.
Who this is actually for
Engineering students
Following coursework or a professor's material originally built around the TI-85.
Calculator hobbyists
Interested in the assembly programming history or the TI-85's place in calculator history.
Khan Academy viewers
Trying to follow along with the exact calculator used on screen.
Anyone with an old unit
Checking whether that TI-85 in a drawer still has any real use today.
Frequently asked questions
Is the TI-85 calculator online actually free?
Yes. No sign up, no subscription, nothing to download.
Why does the TI-85 use F1 through F5 keys instead of buttons like GRAPH or WINDOW?
The TI-85 came out in 1992, before Texas Instruments switched to fixed, permanently labeled buttons. Instead, menu names appear at the bottom of the screen and change depending on what you're doing, and you press the F key directly under the option you want.
Is the TI-85 allowed on the SAT or ACT?
It isn't on any prohibited list since it has no computer algebra system, but it's been out of production for decades, so almost nobody actually brings one to a test today.
What calculator does Sal Khan use in Khan Academy videos?
Sal Khan is commonly seen using a TI-85 in older Khan Academy videos. This online simulator lets you follow along using the same menus and functions.
Should I use a TI-85 or a TI-84 today?
If you're choosing new, get the TI-84 Plus. It's actively supported, uses a simpler button layout, and is required by more schools. The TI-85 is worth using if you already have one, are following older course material, or just want to learn how it works.
Does the TI-85 support programming?
Yes, it runs TI-BASIC, and it was actually the first TI graphing calculator capable of running assembly language programs, discovered through a loophole shortly after its release.