Triangle perimeter calculatorCalculate the perimeter of a triangle instantly from its three side lengths.Side aMillimetre (mm)Centimetre (cm)Metre (m)Kilometre (km)Inch (in)Foot (ft)Yard (yd)+Side bMillimetre (mm)Centimetre (cm)Metre (m)Kilometre (km)Inch (in)Foot (ft)Yard (yd)+Side cMillimetre (mm)Centimetre (cm)Metre (m)Kilometre (km)Inch (in)Foot (ft)Yard (yd)Perimeter—