The Internet Archive Software Collection now includes a bunch of old calculators, including graphing, pocket, and children's calculators. These are all emulated via MAME in the browser and usable with just the touch of a button.

Currently available are:
  • Vtech Electronic Number Muncher
  • Hewlett Packard HP 48G+
  • Hewlett Packard HP48GX
  • Hewlett Packard HP49G
  • Hewlett-Packard HP38g
  • Texas Instruments TI-83 Plus
  • Texas Instruments TI73 Explorer
  • Texas Instruments TI81
  • Texas Instruments TI82
  • Texas Instruments TI85
  • Texas Instruments TI86
  • Texas Instruments TI89
  • Texas Instruments TI92
  • Texas Instruments v200 PDA

Check out the calculator drawer here
calculators hewlett packard texas instruments vtech