A material take off calculator is the step between the drawings and the order: every material on the job listed in the unit it is bought in, with the quantity read off the drawings and the waste the crew will produce added, so the yard can price it and the estimate can carry it. It is the most mechanical part of estimating and the part most often done from memory. This page is the takeoff for the 40 by 30 house used across this site, trade by trade, with the unit and the waste on each line and the reason for both, and it says how to estimate building materials a plan does not draw. The construction cost estimator on this site prices the list at your own rates; the stud, sheathing and drywall calculators work the individual trades.
The unit first: what the yard sells it in
Every line is quantified in the unit it is bought in, because a quantity in the wrong unit is a phone call. Lumber by the piece and length or by the board foot; sheathing and drywall by the sheet; concrete by the cubic yard; roofing by the square, a hundred square feet; insulation by the square foot at a stated depth; nails and screws by the box; paint by the gallon at a stated coverage. The takeoff reads the drawing in feet and converts to the bought unit on the line, and the wood handbook linked below is the reference for lumber sizes and the board-foot rule that the lumber lines convert through.
The framing and sheathing takeoff, worked
From the 40 by 30 plan with 8 foot walls: 140 feet of exterior wall and 90 of partition give the stud count by the stud calculator's rule, the plates as three runs of each wall's length, and the headers by opening; the exterior wall area less openings gives the wall sheathing in sheets; the roof's plan area times the slope factor gives the roof sheathing. Each line carries its waste: a stated share on studs for crooked stock and cut-offs, a share on sheets for the cuts at corners and openings. The residential code's wall construction chapter, linked below, sets the sizes and grades the lines have to be bought in, which the takeoff records so the yard prices the right stock.
The rest of the house: concrete, roofing, drywall, finishes
Concrete from the foundation plan in cubic yards with waste, the concrete calculator on this site working the shapes; roofing from the roof area in squares plus the starter, ridge and flashing lines; drywall from the wall and ceiling area in sheets with the mud and tape from the sheet count, the drywall calculator on this site working it; insulation from the wall and ceiling area at the drawn depth; doors and windows from the schedule, each; finishes from the room schedule by area or by count. The takeoff does not price any of it; it produces the list the estimate prices, and it produces the same list whoever runs it, which is what makes it a calculator and not an opinion.
How to estimate building materials the plan does not draw, and where the list goes
Fasteners, adhesives, flashing tape, house wrap, drip edge, the consumables no plan shows are estimated from the lines that use them: a box of nails per stated count of studs, a roll of wrap per stated area, and the takeoff carries them as lines with that rule beside the quantity so the next job's takeoff uses the same rule. The finished list goes to the yard for pricing and to the construction cost estimator on this site as the quantity column of the estimate, and DrawScheduleWorks Pro keeps the list against the job so the purchase orders can be checked against the takeoff and the invoices against the purchase orders.
Questions people ask about material take off calculator
What does a material take off calculator produce?
A list of every material on the job in the unit it is bought in, with the quantity read from the drawings and the waste added, trade by trade, ready for the yard to price and the estimate to carry.
How is waste handled in a takeoff?
As a stated share per line, different by material: one on studs for crooked stock and cut-offs, another on sheets for corner and opening cuts, another on concrete for the subgrade. The share is written on the line so the next takeoff uses the same rule.
How do you estimate materials the plan does not show?
From the lines that use them, by a rule: a box of fasteners per stated count of studs, a roll of house wrap per stated area. The rule is recorded beside the quantity so it is applied the same way on the next job.