How this calculator works
Stretch wrap use depends on the perimeter of a pallet load and how many turns the operator makes, not only on pallet height. This calculator estimates revolutions from coverage width and overlap, adds anchor turns, and distinguishes film applied around the load from unstretched length used from a roll.
What the calculation does
Estimate the effective vertical advance of each spiral wrap by reducing the film width for overlap. Round up the revolutions needed to cover the load height, multiply by passes, then add separate bottom and top anchoring turns. Each revolution traverses one load perimeter. Divide stretched film length by one plus the fractional stretch to estimate the unstretched roll length drawn.
Important limitations
This is an approximate horizontal-perimeter model; real spiral paths are slightly longer than the perimeter and film is also affected by neck-down, tension, corners, wrapping pattern and load stability. Stretch is not necessarily equal to machine pre-stretch settings.
Common questions
Does 150% stretch mean film is 1.5 times as long?
No. In this calculator 150% extension means the film is 2.5 times its original length.
Does film width change when stretched?
Real film can narrow under tension. Use the effective width actually covering the pallet for a more realistic estimate.
How do I include bottom and top reinforcement wraps?
Add the total extra anchor revolutions across the entire wrapping cycle.