The complete guide to stretch film

Stretch film is bought by the kilo and consumed by the pallet, and almost nobody knows their cost per pallet. That gap is worth money to whoever is selling you film: a lower price per kilo on thicker film with less pre-stretch wins the order and makes your wrapping more expensive.

The cost per pallet calculator does the arithmetic. This is why it works out the way it does.

1. Cast or blown

Two ways of making the same material, and they behave differently.

	Cast	Blown
Made by	Extruding onto a chilled roller	Extruding as a bubble, cooled in air
Clarity	High — labels readable through it	Hazy
Noise off the roll	Quiet	Loud
Cling	Consistent, one-sided available	Aggressive, both sides
Puncture resistance	Lower	Higher
Price	Lower	Higher

Cast is right for most palletised goods. It is quieter, clearer, cheaper and easier to run at high pre-stretch.

Blown earns its price on awkward loads — sharp corners, unstable stacks, anything that has to survive multiple handlings or a long sea journey. It tears less readily once punctured, which is the property that matters when a corner finds it.

If your loads are square, stable and going by road, paying for blown is paying for a property you are not using.

2. Pre-stretch — the whole argument

This is the single largest saving available in most packaging operations, and it costs nothing.

Pre-stretch is the film being elongated before it reaches the pallet, between two geared rollers on the wrapper. At 250% pre-stretch, one metre off the roll becomes three and a half metres on the load. At 150%, it becomes two and a half.

It does not change how much film the pallet needs. That is fixed by geometry — the perimeter, the height, the overlap and the number of turns. It changes how much roll you spend getting there.

A typical European pallet — 1200 × 800 mm, 1500 mm of goods, 500 mm film at 23 µm, 20% overlap, wrapped up and down with two turns at the base — takes ten turns and 40 metres of film on the load, always. What changes is:

	At 150%	At 250%
Film drawn from the roll	16.0 m	11.4 m
Film per pallet	169 g	121 g
Cost per pallet at €2.20/kg	€0.372	€0.266
Pallets from a 15 kg roll	88	124

For a plant wrapping 60 pallets a shift — 13,800 pallets a year — that is €5,139 against €3,671. A saving of €1,468 a year and two thirds of a tonne of polyethylene, for a setting change on a machine you already own.

The catch nobody checks

The calculation assumes the pre-stretch you set is the pre-stretch you get. A carriage set to 250% with worn or slipping rollers delivers nearer 150%, and there is no alarm for it — the pallets still come out wrapped.

The film bill is where it shows. If consumption per pallet has drifted up without the loads changing, measure it directly: mark a metre of film on the roll, run one cycle, and see how far the mark has travelled. It takes five minutes and it has found a four-figure annual leak more than once.

Power pre-stretched film

Film sold already stretched, so it needs little or no pre-stretch on the machine. It is thinner, lighter per pallet, and priced higher per kilo.

It is genuinely the right answer where the wrapper cannot pre-stretch — old machines, and hand wrapping. Where the wrapper can, buying pre-stretched film is paying somebody else to do a thing your machine does for free.

3. Containment force, not tightness

The property that keeps a load on a pallet is containment force — how hard the film squeezes, measured in kilograms of pull. It is not how tight the film looks and it is not how many turns there are.

Two things get confused with it:

• More turns add film without adding much force. A load that shifts does not usually need more wraps; it needs more force per wrap, or a different pattern.
• Thicker film at the same tension gives more force, which is why thickness is used as a substitute for a properly set machine. It works, and it costs about 30% more polyethylene to do it.

The practical test costs nothing: wrap a pallet, then try to move the top layer by hand. If it slides on the layer below, the problem is force, not film.

4. Hand or machine

The threshold is about 30 pallets per shift.

Below it, a wrapping machine is hard to justify on film alone. The machine, its service, its downtime and an operator waiting for it cost more than the film they save.

Above it, hand wrapping gets expensive fast. Hand film is applied with almost no pre-stretch — 0 to 30% is what a person achieves — so the pallet that costs €0.266 by machine at 250% costs €0.716 by hand at 30%, and €0.931 at no stretch at all. A plant hand-wrapping 60 pallets a shift spends roughly €9,883 a year on film where €3,671 would do.

A semi-automatic wrapper pays for itself on the film alone, usually inside a year, before anybody counts the labour.

5. Why a cheaper film can cost more

Same pallet, both at 250% pre-stretch, two quotations:

	23 µm at €2.20/kg	30 µm at €1.95/kg
Price per kilo	—	11% cheaper
Film per pallet	121 g	158 g
Cost per pallet	€0.266	€0.308
Cost per year, 13,800 pallets	€3,671	€4,244

The cheaper film costs 16% more per pallet, because you are buying 30% more polyethylene to do the same job. The price per kilo was the wrong question.

And the core

Rolls are quoted gross. A 0.9 kg core on a 15 kg roll is 6% of what you are weighing — €1.67 a roll for cardboard at €1.85 a kilo. Two quotations at the same price per kilo with different cores are not the same price, and the difference appears nowhere on either document.

Ask what the core weighs. The roll yield calculator turns it into a cost per pallet.

6. Microns and gauge

One gauge is 0.254 microns. 80 gauge is 20 µm, 90 gauge is 23 µm, 120 gauge is 30 µm.

It is the same conversion the sack trade uses, where it gets rounded to four gauge per micron. What differs between the two products is not the scale but what a number means on it: 23 µm is a normal machine film and a very light refuse sack.

7. The specialities, and when they are worth it

• Coloured film — black for concealment, colours for line identification. Adds cost and removes the ability to see the load. Worth it for security, not for tidiness.
• UVI film — for loads stored outdoors. Ordinary film embrittles in sunlight within weeks; UVI holds for around twelve months. If pallets go outside, this is not optional.
• Macro-perforated — for produce and anything that has to breathe. Do not use it as a substitute for ventilated packaging.
• Bundling film — narrow, for holding a few items together rather than wrapping a pallet. Much cheaper per pallet than using a full-width roll badly.

8. What a quotation should state

Line	Why it matters
Thickness in microns	Gauge alone invites the rounding argument
Width in mm	Sets how many turns cover the height
Net roll weight, and the core weight separately	A gross weight hides the core
Metres per roll	The figure that makes prices comparable
Cast or blown	Different products at similar prices
Pre-stretch the film is engineered for	A film run beyond its design tears
Rolls per case, cases per pallet	It decides the freight

What to send us

Your current specification, the pallet count, and what your wrapper is set to. We will run the cost per pallet against what you buy today.

If the answer is that your existing supplier is already competitive, that is what we will tell you. It is a shorter conversation than the alternative, and it happens more often than you would expect — the saving is usually in the wrapper settings rather than in the film.