The app Units - Simply Convert lets you to quickly convert between units.
Functions:
• Browse different unit categories like Area, Pressure or Speed. Unit values of the selected category are converted instantly.
• A second tap on a unit allows the adjustment of its value. Again all other units of the selected unit category are converted instantly.
• Switch between three display modes for unit values (decimal, scientific and automatic). Automatic mode switches from decimal to scientific notation if unit values exceed the visible area.