Classic Internet online unit converter is designed to input one single value to receive one converted value. Conversion of more then one unit, like feet and inches to centimeters, requires frequent switching between converters, annoying, time consuming process which may lead to errors.

This work describes new formats of online units' converters and dedicated calculators, to significantly improve the conversion or calculation efficiency, receiving more useful and more handy information in less effort.

The improvements of new forms of online converters and calculators include:

·ComboBox

·Changing both units without “submit” button

·Few sets of data

·All relevant units together

·Feet plus inch in the same converter

·Default values in online complex calculators

·Comparing values between sets of data

·Auto-fill of input fields

·Automatic fill with specific pattern

·Correcting not reasonable inputs

·Automatic input of recommended value

·Automatic determination of input limits

·Automatic input of recommended value

·Using calculators for optimization