Convert is designed as a conversion calculator but will also be useful as an ordinary calculator (non-scientific in present version). Convert can convert from and to combined units such as: 3 pounds AND 5 ounces. Kilograms. 6 metres. Feet AND inches. 0. 73 hours. Minutes AND seconds. 16. 2 litres. Gallons AND pints. Categories of units include: Length. Weight. Volume. Time.