What is the main difference between LDPE and HDPE?

Chain structure, and everything that follows from it. LDPE has highly branched chains that pack loosely, making it soft, flexible, clearer and easy to heat-seal. HDPE has mostly linear chains that pack tightly, making it stiffer, stronger per gram, more opaque and harder to seal. Same monomer, different manufacturing pressure.

Which is stronger, LDPE or HDPE?

HDPE has higher tensile strength per unit weight, so for a given thickness it resists a pull better. LDPE stretches much further before it fails, which in packaging often matters more, because a bag that deforms around a corner beats one that tears at it. Strength is not one number, it depends on whether your failure mode is pulling, puncturing or tearing.

Is LDPE cheaper than HDPE?

Per kilo they are broadly similar, because both are made from ethylene and both track the same feedstock. The real cost difference shows up in how much material a job needs: HDPE is stronger per gram, so an HDPE product can often be thinner. Anyone quoting a big price gap between the two is telling you about their supply position, not about the polymers.

Which is better for food packaging?

LDPE, for most flexible food packaging. It seals reliably at low temperature, it is soft enough not to damage the product, and it is clearer. HDPE is used for food too, mostly in rigid form like milk jugs and containers. Both can be food grade with virgin resin and proper testing.

How can I tell if a bag is LDPE or HDPE?

Scrunch it. HDPE crinkles loudly and feels papery. LDPE is quiet and soft. Then stretch a strip: LDPE stretches and thins before snapping, HDPE tears in a fairly straight line. HDPE is also milky even when thin, where LDPE is more translucent. For certainty, send us a sample and we will measure it.

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LDPE vs HDPE: the difference that matters when buying

We make LDPE, so treat this page accordingly. It also means we lose money every time someone buys the wrong one from us, which is why the decision table below sends you to HDPE for four applications.

Ask which one you need →

IN ONE LINE

LDPE is soft, stretchy and seals easily. Choose it for flexible packaging, liners, film, sheet and anything heat sealed.
HDPE is stiff, strong and holds its shape. Choose it for bottles, crates, pipes, carrier bags with handles and long-life liners.
Same raw material, different manufacturing pressure, completely different behaviour.
HDPE is stronger per gram, so an HDPE bag can be thinner than an LDPE bag for the same strength. That is why it crinkles.

Side-by-side comparison

Property	LDPE	HDPE
Density	0.910 to 0.925 g/cm³	0.941 to 0.965 g/cm³
Chain structure	Highly branched, loosely packed	Mostly linear, tightly packed
Made at	Very high pressure, 1,000 to 3,000 atm	Low pressure with catalysts
Feel	Soft, flexible, quiet	Stiff, crinkly, makes noise
Clarity	Translucent, can be fairly clear	Milky, opaque
Melting point	Approx. 105 to 115 °C	Approx. 120 to 130 °C
Tensile strength	Lower, but stretches a long way before breaking	Higher, less stretch
Heat sealing	Excellent, low temperature, forgiving	Harder, needs more heat and precision
Puncture resistance	Good, it deforms rather than splitting	Good per unit weight but more likely to tear once nicked
Chemical resistance	Very good	Excellent, better with solvents
UV resistance	Poor without stabiliser	Poor without stabiliser
Resin code	4	2
Cost per kg	Broadly similar, both track ethylene	Broadly similar, both track ethylene

Note the last row. People assume one is cheaper. They track the same feedstock, so the real cost difference in use comes from how much material each job needs, and HDPE often needs less because it is stronger per gram.

Which one for your job

The practical version. Four of these send you away from us, and that is deliberate.

Application	Buy	Reason
Bread, produce, food bags	LDPE	Soft, clear, seals reliably at low heat. Food contact standard.
Drum and container liners	LDPE	Needs to drape into the container and not split at the fold.
Curing sheet, DPC, covers	LDPE	Needs to lay over uneven surfaces without tenting.
Courier and garment mailers	LDPE	Seal reliability and a soft feel that does not scuff goods.
Milk pouches, FFS film	LDPE / LLDPE blend	Seal window is everything on a form-fill-seal machine.
Carrier bags with punched handles	HDPE	Handles need stiffness and tear resistance at the punch.
Bottles, jerrycans, containers	HDPE	Must hold a shape under its own weight.
Pipes, crates, pallets	HDPE	Structural. LDPE would deform.
Permanent pond and landfill liners	HDPE geomembrane	Decades of stress. LDPE is a short-term stopgap only.

And where does LLDPE fit in?

LLDPE (linear low-density polyethylene) is the third member of the family and the one nobody explains. It has LDPE's low density but linear chains with short branches, made with catalysts rather than brute pressure. In practice it is tougher than LDPE in tear and puncture, which is why it dominates stretch film.

Most real-world film is a blend. We routinely run LDPE-LLDPE blends because you get LDPE's sealing behaviour and processing ease with a useful lift in strength, which lets you go a step thinner for the same performance. Full explanation on LDPE vs LLDPE.

How to tell them apart with your hands

Useful when a supplier sends you something and the invoice says one thing.

Sound. Scrunch it. HDPE crinkles loudly. LDPE is quiet.
Stretch. Pull a strip slowly. LDPE stretches and thins before it snaps. HDPE gives a little then tears in a straight line.
Clarity. Hold it to light. LDPE is translucent to fairly clear. HDPE is milky white even when thin.
Stiffness. Hold a strip horizontally. HDPE stands out further before it flops.

And if you need certainty rather than a feel test, send us a sample. We will measure it and tell you what it is.

Keep reading

What is LDPE?

The polymer explained from first principles, with the numbers.

LDPE vs LLDPE

The comparison that actually decides most film specs.

Our LDPE products

Bags, sheet, film and covers, with specs and micron ranges.

LDPE vs HDPE questions

Not sure which one your job needs?

Describe the application in one paragraph. We will tell you LDPE, HDPE or something else, and we will say so even when the answer costs us the order.