Determine the length, width, thickness and web length of your metric beam either by measuring these dimensions with a metric tape measure or reading the dimensions on the side of the beam.
Convert the length, width, thickness and web length of your beam from millimeters to inches using the equation "inches = millimeters x 0.0394." Multiply each linear dimension of your beam by 0.0394. So if your beam is 200 mm in length and 150 mm wide, the measurements will be converted to 7.874 inches in length and 5.9055 inches wide.
Determine the weight of your metric beam as kilograms per meter (kg/m) by using a metric tape measure and weight scale or by reading the information on the side of the beam.
Convert the metric weight of your beam to pounds per feet using the equation "pounds/feet = kg/m x 0.6719969." Multiply the metric weight per meter of your beam by 0.6719969. So if your beam is 26 kilograms per meter, the measurement will be 17.4719194 lb. per foot.