Free tool

Scientific calculator

Laid out like the Casio fx-991 you already own — SHIFT for each key's second function, DEG/RAD, memory and Ans. Works offline once the page has loaded, and nothing you type leaves your device.

⬇ Download the Windows app Free · 78 MB · Windows 10 / 11 · no account — or just use it below, nothing to install
DEG
 
0

Your working

Worth knowing

  • Type with your keyboard: digits, + - * /, ^, Enter to evaluate, Esc to clear.
  • Shortcuts: s sin, c cos, t tan, r √, l log, n ln, p π.
  • Press SHIFT then a key for the small label above it — inverse trig, cube root, 10x, nCr and nPr.
  • Ans reuses the last answer. Starting a line with an operator continues from it, exactly like the handheld.
  • Click any line of your working to put it back on the display.

Windows app

Download the Windows app

The same calculator as a small desktop window you can keep beside your notes — no browser, no internet, nothing to sign in to. Windows 10 / 11, 64-bit.

⬇ Download for Windows Free · 78 MB · no account
Windows will warn you twice — here's why, and what to click

While downloading, your browser may say the file “isn't commonly downloaded”. Open the Downloads panel, click the … beside the file and choose Keep. When you run it, SmartScreen may show a blue box — click More info, then Run anyway.

Neither means anything is wrong with the file. Windows shows this for any new program without a code-signing certificate, and those cost several hundred dollars a year — which we'd rather not add to a free app.

To check you got the real file, run Get-FileHash <file> in PowerShell and compare it with:

dbea83fc50587079ff92ef7be2368f0c97665efd0e6001c517d1cafea2118322