12/8/16: Feature tweaks. Thanks for the feedback! A few tweaks:
Bugfix - InstaCalc wasn't displaying on certain older browsers (Safari 8, IE10), which has been fixed.
Feature - the "clear" button has been added (thanks for the suggestions).
Feature - tooltips have been added for the calc commands below the last row.
12/5/16: Major Update: It's a whole new InstaCalc. This release brings numerous improvements, including:
Google Login - sync your calcs to the cloud, access them from any device.
Responsive Interface - completely new design, mobile-friendly.
Interactive Help - calcs show (not tell) how to do use various commands.
New Features - easy calc cloning, copying just the text from a calc.
The previous version is available here for comparison. Hope you enjoy it!