Net quantity and order quantity
The takeoff gives the net quantity. That is what the drawings show installed. The order quantity is what you must buy to install it. The waste factor is the difference between the two.
Where waste comes from
- Cuts. Sheet goods, pipe and flooring are cut to fit, and the offcut is often scrap.
- Laps and seams. Membranes and fabrics overlap.
- Pattern and layout. A diagonal tile layout wastes more than a straight one.
- Breakage and damage in shipping and handling.
- Stock sizes. You buy full lengths, full boxes and full rolls.
- Mistakes in the field.
What sets the size of the factor
There is no single correct number. It depends on the material, the room shapes, the layout and your crew. Small rooms with many corners waste more than large open rooms. Your own job history is the best source. Compare what you bought to what you measured on past jobs.
Items that get no waste
Counted items do not get a waste factor. You do not buy a fraction of a door or a basketball backstop. For some counted items you may carry spares. Carry them when the spec requires attic stock or extra material.
Keep waste visible
- Record the net quantity from the takeoff.
- Apply the factor in its own column.
- Round up to the stock size you can buy.
- Show the order quantity last.
A factor hidden inside the measured number causes trouble later. The next estimator adds waste again. Or the project manager orders from the net number and runs short. Keep the three numbers apart.
Bidding and estimating · Updated 11 Nov 2026