Worked example
You need 50 #4 bars, each 20 ft long. One bar weighs 20 × 0.668, or 13.36 lb. 50 bars weigh 668.00 lb. That is 0.334 short tons, or 303.00 kg. With 5 percent added for laps and cut-offs the order weight is 701.40 lb.
Where this bar is used
The #4 bar, at 1/2 inch, is one of the most common sizes on houses and small commercial work. Slabs on grade, driveways, footings, masonry walls and small retaining walls often call for it. The plans set the spacing.
Because #4 is so common, yards stock it in many lengths and often sell it by the bundle. Ask the yard how many pieces are in a bundle before you convert a count to tons.
#4 compared with nearby sizes
A #4 bar weighs 78 percent more per foot than a #3 bar (0.376 lb/ft). A #5 bar weighs 56 percent more than a #4 bar (1.043 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.