Instacalc is a free web based calculator that performs not just basic math but also advanced math as well as conversions between different number systems and units.
Access Instacalc and enter the required parameters in any of the given input fields (R1-R10). The results will be automatically displayed on right side.
The results can be directly saved as a link and sent or be used for future references if needed using the “Link” icon.
Pretty handy online tool if using the default Windows calculator seems boring.