Quail 4+

Quail is a convenient unit conversion app that stays out of your way when you don't need it. Designed to be quick and non-intrusive in all aspects, Quail remembers the last selected measurement units for each conversion type as well as the previously entered conversion values.

Quail can perform the following conversions in various units: 

- Acceleration
- Angle
- Area
- Concentration of Mass
- Electric Charge
- Electric Current
- Electric Potential Difference
- Electric Resistance
- Energy
- Frequency
- Fuel Efficiency
- Length
- Pressure
- Speed
- Power
- Temperature
- Time
- Volume
- Weight & Mass

Both forward and reverse conversions are supported.

Note: Qual in Big Sur is now a small app instead of a widget. Widgets in Big Sur do not support text input, so we could not update Quail to use the new widget APIs.