TI-59 emulator, online
The calculator above is a working Texas Instruments TI-59 emulator running in your browser — no install, no account, nothing to download. It is the Calc-U 59 app's own emulator — the same code the Mac, Windows and Linux apps run — compiled to WebAssembly, executing the original TI-59 ROM. The debugger and the printer are not part of this build; everything else works.
Module 01 (Master Library) is loaded by default. Switch modules (that resets the calculator, as swapping the real module did), load one of the curated presets, or upload your own .ti59 file below the keyboard — uploads are read entirely in your browser and never leave your machine. For more programs to try, including several that need the full app's PC-100 printer, see the TI-59 Software Collection.
Press 2nd then Pgm then a two-digit program number to bring up that program's cue card, the same way it works on the module itself.
Queue Card passes a virtual magnetic card through the reader. To save a program, press 2nd Write (bank 1: 1 2nd Write), then Queue Card. To load it back, press Queue Card while the calculator is idle and it reads the card. The card starts blank and keeps whatever was last written until you leave the page.
For the TI-58 and TI-58C models, the PC-100C printer, card files you keep and the CPU debugger, use the full app: free on the Mac and on Windows and Linux, or on the App Store for iPhone and iPad. If you are not sure what any of this is, start here.
Prefer this without the browser chrome? Open the standalone app — the same calculator alone at its own address, installable to your phone's home screen for a one-tap, full-screen launch.
Use your keyboard
Click the calculator once and it takes your keystrokes — a golden outline shows when it has them. Click anywhere else, or press Tab, and the page gets the keyboard back.
The number keys, the yellow operation keys, A–E, and EE ( ) are typeable. Everything else — 2nd, STO, RCL, LRN and the rest — is click-only, so the keyboard stays out of the way of the page. Holding Shift while you press a letter gives you that key's second function: Shift + A is A'.