Where the film hangs or lies flat and takes no abuse, such as dust walls, drop covers, equipment and pallet covers, 4 mil is enough. Step up to 6 mil the moment film touches the ground, gets walked on, dragged, tensioned, or reused. 2 mil is disposable masking. The difference is material: 6 mil is 0.006" of polyethylene, half again as thick as 4 mil, and that margin is what survives gravel, fastener heads, and boot traffic.
SCOPE: this page compares sheeting and film rolls. Sizing poly bags? Use 2 vs 4 mil poly bags or 4 vs 6 mil poly bags instead.
Start from the abuse the film takes, not the number on the roll. Find your row, read the verdicts, start with a real SKU.
| What the film does | 2 mil | 4 mil | 6 mil | Start here |
|---|---|---|---|---|
| Light coveringpaint masking, single-use dust sheets | BestSingle use, no load, disposed after the job. | OKWorth it only if the drop cover gets reused. | SkipWeight and thickness the job never uses. | 12' × 200' 2 mil clear → |
| General protectiondust walls, doorway curtains, equipment covers | SkipSingle-use film: walls and covers get bumped. | BestHangs or drapes under its own weight and tapes up without sagging. | OKStep up if the cover is dragged on and off often. | 6' × 100' 4 mil black → 20' × 100' 4 mil clear → |
| Abrasion & heavy dutyground cover, boot traffic, drag, tie-down tension | SkipNo margin against gravel or fasteners. | RiskyUnder-speccing: a torn barrier costs more to redo than the thicker roll did. | Best50% more material is the puncture and tear margin. | 12' × 100' 6 mil → 20' × 100' 6 mil → |
| Vapor & long termmoisture barriers under stored goods, reusable covers | SkipA barrier only works while it is intact. | OKIndoors, short term, nothing bearing on the film. | BestSurvives loading over film and deploy-fold-store creases. | 8' × 100' 6 mil → 6' × 100' 6 mil · case → |
A written spec beats every row above: if plans or an inspector name a minimum thickness, match it exactly: a 4 mil substitution saves little and can fail the inspection. Choosing bag thickness instead? That decision lives on the 2 vs 4 mil and 4 vs 6 mil poly bag pages.
Mil is the unit; sheeting, bags, and tubing are the formats it comes in. Every SKU below is real and in the Packrift catalog: open one for current dimensions and case counts.
A mil is one thousandth of an inch. The whole comparison is 0.002" vs 0.004" vs 0.006" of polyethylene: thickness is the spec, everything else follows from it.
Terms before specs: packaging glossary
Choose a sheet wide enough to cover the span in one piece. The comparison below pairs 4 mil and 6 mil rolls by size and color.
Browse: poly film family · construction & contracting
Same unit, different job. A bag usually rides inside another shipper, so it needs handling margins, not ground-contact margins: the thickness logic carries over at bag scale.
Size them right: poly bag size chart · 2 vs 4 mil bags · 4 vs 6 mil bags
A continuous film sleeve: cut to the length of the item, seal both ends, and you have made a bag no catalog stocks. Long, narrow items wrap faster in tubing than in sheeting.
Browse: poly tubing
Cutting sheeting into pallet covers works once. If the same pallet footprint gets covered every week, pre-sized covers from the pallet covers & liners collection drop over the load in one motion, no cutting table. And when film is one line on a bigger jobsite order, the construction & contracting collection keeps it all on one freight charge.
Five checks, same order every time. Most wrong buys skip straight to step four.
Ground contact, boot traffic, drag, or tie-down tension means 6 mil. Film that hangs or lies flat unbothered is 4 mil work. Disposable masking is 2 mil.
If plans or an inspector name a minimum mil, buy that number. A thinner substitution saves little and can fail the inspection.
Measure the span you need to cover and choose a sheet wide enough for the job. Compare width and length on the product page before ordering.
Need to inspect what is covered without lifting the film? Clear: 4 mil at 16 and 20 ft. Need light blocked or contents hidden? Black. Every 6 mil width, plus 4 mil at 3–8 ft.
At the same width and length, a 6 mil roll carries 50% more polyethylene than a 4 mil roll: about half again the weight on the truck. That is the honest cost of the puncture margin: buy it where the job needs it, not everywhere. Under-spec and the tear costs a redo; over-spec and every roll freights material the job never touches.
Carriers bill the greater of actual and dimensional weight. A dense film roll usually bills its scale weight, but a bulky, boxed roll with air around it can flip to dim weight instead, so on small orders, freight can rival the roll itself. Order full rolls and combine film with the rest of the supply order so one charge spreads across everything. Shipping the goods the film protected is the other half of the math: the box-size guide covers the outbound cube.
Open the cost & cube index →Six mil under a gravel pad is cheap insurance. Six mil on a doorway curtain is freight with no job. Match the mil to the abuse.
Use 6 mil when the film touches the ground, carries traffic, gets dragged or tensioned, or will be reused. Use 4 mil when the film hangs or lies flat without abuse: dust walls, drop covers, equipment and pallet covers, and short-term moisture and dust protection.
6 mil is 0.006 inch and 4 mil is 0.004 inch, so 6 mil is 50 percent thicker. That extra material is what resists punctures from gravel, fasteners, and corners, and it is why 6 mil is the default once film meets the ground.
A mil is one thousandth of an inch, so 4 mil film is 0.004 inch thick. Mil is not a millimeter; 4 mil is close to 0.1 mm. Stretch film specs often use gauge for the same idea, where 100 gauge equals 1 mil, and the same unit describes poly bags, sheeting, and tape backing.
The unit is identical, but the job is different. A bag is usually an inner layer inside another shipper, while sheeting often faces ground contact, wind, and traffic on its own. Compare bags on the 2 vs 4 mil and 4 vs 6 mil poly bag pages, and compare sheeting on this page.
4 mil runs from 3 to 20 feet wide and 6 mil from 6 to 20 feet wide, in 100 foot roll lengths, with a 12 foot by 200 foot roll at the 2 mil tier. Pick a width that covers the span in one piece and confirm current details on the product page.
PACKRIFT · Match the mil to the abuse, cover the span in one piece. Confirm current widths, lengths, and case counts on each product page before ordering.
Need the numbers in microns or millimeters? The mil to micron conversion chart covers 0.5 to 10 mil and stretch film gauge.
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Current edition: a standard 12 x 12 x 12 box runs a median $1.62 in bundles, and freight adds a median 48% on top of product price.
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