How to Calculate PE Film Weight: Formula, Worked Example and a Free Calculator

To calculate PE film weight (core excluded), multiply length (m) x width (m) x thickness (m) x PE density (kg/m3). For example, a 300 m x 0.5 m roll at 17 micron and 920 kg/m3 weighs 2.346 kg of film; add a 0.5 kg core for a 2.846 kg total roll. This guide gives the formula, explains each input, and includes a free calculator that estimates film usage, weight and cost per pallet, per day and per month.

Why you need to know how to calculate PE film weight

Knowing how to calculate PE film weight delivers several practical benefits for packaging and logistics teams:

• Cost control: estimate PE film cost accurately for each order or production run.
• Inventory management: track remaining film and plan reorders in time.
• Performance benchmarking: compare film consumption across processes or shifts.
• Quality checks: reconcile actual roll weight against the supplier’s specification.

The PE film weight formula

To calculate the weight of PE film (core excluded), use this basic formula:

• Film weight (kg) = Length (m) x Width (m) x Thickness (m) x PE density (kg/m3)

Then, to get the total roll weight, add the weight of the core:

• Total roll weight (kg) = Film weight (kg) + Core weight (kg)

What each input in the formula means

To apply the PE film formula accurately, you need to understand each component:

• Length (m): the total length of the PE film roll, usually provided by the manufacturer in metres.
• Width (m): the roll width, converted to metres if it is given in centimetres (for example, 50 cm = 0.5 m).
• Thickness (m): film thickness is usually measured in microns (um). Convert microns to metres for the calculation: 1 um = 0.000001 m. For example, 17 micron film is 0.000017 m.
• PE density (kg/m3): the density of the polyethylene material. For LDPE commonly used in stretch film, density is typically 0.91-0.94 kg/m3. You can use an average of 920 kg/m3 (equivalent to 0.92 g/cm3) or request the exact figure from the supplier.
• Core weight (kg): the weight of the paper or plastic core inside the roll. The supplier usually provides this, or you can weigh it yourself.

Worked example: calculating PE film weight

Let us apply the PE stretch film formula to a specific example. You have a PE film roll with these specifications:

• Length: 300 metres
• Width: 50 cm (that is, 0.5 metres)
• Thickness: 17 micron (that is, 0.000017 metres)
• PE density: 920 kg/m3
• Core weight: 0.5 kg

Step 1: calculate the film weight (core excluded)

Film weight = Length x Width x Thickness x density

Film weight = 300 m x 0.5 m x 0.000017 m x 920 kg/m3

Film weight = 2.346 kg

Step 2: calculate the total roll weight

Total roll weight = Film weight + Core weight

Total roll weight = 2.346 kg + 0.5 kg

Total roll weight = 2.846 kg

So your PE film roll has a total weight of about 2.846 kg.

Quick reference: common PE film weights

Film weight only, core excluded, at PE density 920 kg/m3. Add the core weight (typically 0.3-0.6 kg) for the total roll weight.

Frequently asked questions about PE film weight

1. How do you calculate PE film weight?

Multiply length (m) x width (m) x thickness (m) x PE density (kg/m3). Convert width from cm and thickness from microns to metres first, then add the core weight for the total roll weight.

2. What density should I use for PE stretch film?

LDPE stretch film density is typically 0.91-0.94 kg/m3. Use an average of 920 kg/m3 (0.92 g/cm3) for estimating, or ask the supplier for the exact figure.

3. How do I convert microns to metres for the calculation?

1 micron = 0.000001 m. For example, 17 micron = 0.000017 m and 20 micron = 0.00002 m. Always convert thickness to metres before applying the formula.

4. Why is the total roll weight higher than the film weight?

The formula gives the film weight only. The total roll weight adds the paper or plastic core, usually 0.3-0.6 kg, so the figure on the label is higher than the calculated film weight.

5. How much film does it take to wrap one pallet?

It depends on pallet size, load height, overlap and stretch. Use the calculator above: a standard 120 x 100 cm pallet at 150 cm typically uses around 135 g of film per pallet at the industry norm, and a stretch wrapper can cut usage by roughly 29% versus hand wrapping.

6. Does machine wrapping really save film?

Yes. A stretch wrapper applies higher, more consistent stretch (around 250% versus about 150% by hand), so it covers the same surface with less film. The calculator estimates the saving for your inputs.

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