A rebar takeoff requires that you count and measure all rebar in your footings and walls. The more common name for this process is called estimating. Failure to complete a thorough takeoff can result in lost time and money. Even if you have little or no experience, you can complete a rebar takeoff in four to 12 hours, depending on the size and scope of the project.
Measure the width and length of your footers, and record the measurements onto a writing pad. Footers 24 inches wide require three sticks of rebar, and 16-inch-wide footers require two. Because rebar is manufactured in lengths of 20 feet, divide the total footer length by 20 to get the total number of sticks of rebar. For example, if you have a total footer length of 100 feet, then you need five sticks of 20-foot rebar.
Multiply the total rebar by the number of sticks required for your footer width. For example, multiply 3 (24-inch-wide footer) times 5 (number of 20-foot sticks in a 100 foot long footer) to get 15. If you have a 16-inch footer, then multiply 5 times 2 to get 10.
Calculate the cross bars (rebar that lies across the 20-foot rebar sticks). Divide the total footer length by 24 inches (cross bar spacing) and multiply that by the footer width (16 or 24 inches). For example, if you have a footer that is 100 feet long, divide 100 by 2 to get 50. Take the footer width (16 or 24 inches) and multiply that by 50 to get a total rebar amount for the cross bars.
Calculate wall rebar; divide the total length of the wall by 2 feet (rebar spacing) and multiplying that by the wall height. For example, divide a 20-foot wall by 2 to get 10 (number of rebar spaced at 2 feet. Multiply that number by the wall height to get the total feet of rebar required for the wall.