Worked example
You need 50 #3 bars, each 20 ft long. One bar weighs 20 × 0.376, or 7.52 lb. 50 bars weigh 376.00 lb. That is 0.188 short tons, or 170.55 kg. With 5 percent added for laps and cut-offs the order weight is 394.80 lb.
Where this bar is used
The #3 bar is the smallest size in common structural use. It is light and easy to bend, so it goes where the steel is thin and the loads are small. Typical jobs are stirrups and ties in beams and columns, light patio and walkway slabs, and vertical bars in masonry cells.
Many builders buy #3 bars already bent to shape. Weigh each bent shape by its unfolded length, not by the box it fits in. The calculator above works from the unfolded length.
#3 compared with nearby sizes
A #4 bar weighs 78 percent more than a #3 bar (0.668 lb/ft). Moving one size up adds weight fast, because weight follows the area of the bar. Check the plans before you swap one size for another.