Downgauging: thinner film and tape without losing strength

Downgauging means using a thinner film, tape or paper that still does the same job. A 60 micron bag becomes a 50 micron bag. A tape with a heavier backing becomes one with a lighter backing.

The parcel must still arrive in one piece, or the saving is gone.

It saves money for a simple reason. You buy film by the kilogram, but you use it by the square metre. A thinner film gives you more square metres from every kilogram.

But downgauging is not the same as ordering thinner material and hoping for the best. It works when a better polymer, a better structure or a better process makes up for the microns you remove.

And it works only after a trial on real orders proves it.

We make tapes and films in Jaipur, and downgauging is a lever we use in our own production. I would still rather you go slowly, which is why this guide spends as much time on the trial as on the saving.

We start with the arithmetic, then the legal floors in India and a trial method. The calculation per 1,000 orders, which you can repeat with your own figures, comes at the end.

Why does a thinner film cost less?

Because the weight of a film follows its thickness.

Here is the rule. Grams per square metre = thickness in microns × density in g/cm³.

Polyethylene film is often around 0.92 g/cm³, but take the real figure from your supplier's data sheet. I use 0.92 below only as an assumption, for illustration.

Going from 60 to 50 microns gives you about 20% more film from every kilogram.

This leads to a rule of the trade that I would put on the wall of every purchase office. Never compare films on price per kg alone.

A better grade may cost more per kg and still cost less per square metre, because you need fewer grams of it.

Take two films, with prices that are assumed for this example only. Film A is 60 microns at ₹170 per kg. Film B is a tougher 50 micron grade at ₹185 per kg.

1. Film A: 55.2 g per m² × ₹170 per kg = ₹9.38 per m².
2. Film B: 46.0 g per m² × ₹185 per kg = ₹8.51 per m².

Film B is dearer per kg and about 9% cheaper per square metre.

If it passes your tests, it is the cheaper film.

How can a thinner film be just as strong?

Think of a good roti. It is thin, and it still does not tear when you fold it, because the dough and the hands are right. Thickness alone was never the source of its strength.

Film is similar, and this is the part a price list cannot show you: its strength depends on the polymer grade and the structure of the film as much as on the number of microns printed on the label.

1. Newer polyethylene grades, such as metallocene LLDPE, generally resist impact and puncture better than older general-purpose grades at the same thickness. They are not better at everything. Some of them tear more easily along the length of the roll, which is one reason film makers blend grades.
2. A multilayer film can put each grade where it is needed. A tough layer, a sealing layer and a layer for print can each do one job, instead of one thick layer doing all three jobs half well.
3. Better process control gives a more even film. When the thinnest spot of a roll is closer to the average, you need less safety margin in the average.

These are the levers we work with on our own lines. In 2025, our own work on reducing plastic came down to three things: better polymers, downgauging without losing strength, and paper in place of plastic where paper does the job. This guide is about the first two.

I cannot tell you from here how thin your film can go. That depends on your product, your machines and your route to the customer.

Only a trial can tell you, and I would not trust anyone who promises a number without one.

Where does downgauging work, and where does it not?

It tends to work where the film or tape has strength to spare:

1. Courier bags and mailers for clothes and soft goods.
2. Liners and covers that only keep dust and moisture out.
3. Tape on light cartons that are not stacked high.
4. Stretch and shrink films, when the grade and the machine settings change together.

I would be careful in these places:

1. Heavy products, or products with sharp corners that can puncture the film.
2. Automatic machines set up for one particular film. A thinner film can wrinkle, stretch or break on the machinery even when it is strong enough in the parcel.
3. Cold warehouses and winter months. Film gets stiffer in the cold, and tape adhesive grips less.
4. Recycled or dusty cartons, where a lighter tape may lift.
5. Barrier films for food. The barrier layer is chosen for shelf life, so do not touch it without a proper shelf-life evaluation.

What is the legal minimum thickness in India?

Downgauging stops at the law. I would check this before any trial, because two floors in the Plastic Waste Management Rules matter for packaging.

1. Plastic carry bags must be at least 120 microns thick since 31 December 2022. This came from the amendment notified on 12 August 2021, as the Press Information Bureau release of 21 July 2022 explains.
2. Plastic sheet or like used for packaging or wrapping, which is not part of multilayered packaging, must be at least 50 microns. The rule allows exceptions only as specified by the Central Government, where that thickness would impair the product's function. The 50 micron floor for plastic sheets was set by the 2016 rules, as the Press Information Bureau release of 18 March 2016 records.

States can be stricter. The 2022 release above notes that 34 states and union territories had issued their own complete or partial bans on carry bags or single-use plastic items, over and above the central rules.

Whether a particular bag, liner or wrap counts as a "carry bag" or a "plastic sheet" under these rules is a legal question. Confirm it with your compliance advisor before you order anything thinner. A bag that breaks the rules will cost you more than the film it saved, on the day someone checks.

How to run a downgauging trial

This is the method we suggest. It is slow on purpose, and I am comfortable with that.

1. Measure what you use today. You need a baseline, and you need to know whether the material you actually receive matches the specification.
2. Write down pass and fail before you start. For example: no bursts or seal failures in the trial orders, no breaks on the machine, and no rise in complaints.
3. Change one thing at a time. A new thickness, a new grade and a new supplier at once will leave you guessing about what made the difference.
4. Step down gradually, a few microns at a time, and stay above any legal floor that applies to your item.
5. Run it on real orders, with your heaviest and sharpest products included. A test in the office tells you less than a few weeks of real dispatch.
6. Include a cold month or a monsoon month if you can, or repeat a short trial when the season changes.
7. Adjust the machines. Sealing temperature, dwell time and wrap tension may need to change for the new film.
8. Track failures by lot and by date. If complaints rise, you will know which material caused it.

You can check film thickness yourself without a laboratory. I like this check because anyone in your stores can do it in five minutes. Cut a piece 20 cm × 50 cm, which is 0.1 m². Weigh it on a scale that reads to 0.1 g. Multiply the grams by 10 to get grams per m², then divide by the density. A 50 micron polyethylene film at 0.92 should weigh about 4.6 g. This gives you the average thickness. A micrometer will show you the thin spots as well.

For tape, ask your supplier to state the film thickness and the adhesive weight separately, as well as the total. Any serious supplier should be able to give you all three figures.

Then test the thinner tape on your heaviest carton, in your coldest month.

Your calculation: the saving per 1,000 orders

Every figure in this example is an ASSUMPTION, chosen only to show the method. None of them is a market price or our price.

Take a courier bag of 32 cm × 40 cm with a 5 cm flap. The example stops at 50 microns on purpose, because of the floor for plastic sheet described above. The film area is the front (32 × 40 cm) plus the back with its flap (32 × 45 cm). That is 2,720 cm², or 0.272 m².

1. At 60 microns: 0.272 m² × 60 × 0.92 = 15.0 g of film per bag.
2. At 50 microns: 0.272 m² × 50 × 0.92 = 12.5 g of film per bag.
3. Saving: 2.5 g per bag, which is 2.5 kg per 1,000 orders.
4. At an assumed film price of ₹180 per kg, that is ₹450 per 1,000 orders, or 45 paise per order.
5. At 1,00,000 orders a month, it is ₹45,000 a month, and 3 tonnes less plastic a year.

Only the material part of the bag price falls, because printing and bag-making cost about the same per piece whatever the thickness. So ask your supplier to show the material and conversion parts of the price separately.

Now the part that is easy to skip, and the part I care about most.

The saving is 45 paise per order. Suppose one damaged delivery costs you ₹1,200 (assumed). Then a single extra failure in every 2,667 orders wipes out the entire saving, because ₹1,200 ÷ ₹0.45 is about 2,667.

That is why, for us, the trial matters more than the price. Our worksheet on what a damaged delivery really costs shows how to get your own figure for that ₹1,200.

The 3 tonnes also count for plastic EPR, which is worked out on the weight of plastic packaging you put on the market. See our guide to plastic EPR for brand owners.

To repeat this with your own figures:

1. Film per order (g) = area per order (m²) × microns × density.
2. Saving per 1,000 orders (₹) = (old g − new g) × film price per kg.
3. Break-even failures = saving per order ÷ cost of one damaged delivery. If the trial shows more extra failures than this, stay with the thicker film.

If you want help with the numbers or a trial plan, send us your current film or tape specification and your monthly volume through the contact page.

If your current specification is already right, we will say so. Honestly, that is a good result too.