Aluminium foil thickness: 10, 12, 15 or 18 micron?
Thickness is the single biggest lever on cost and the easiest thing to get wrong, because a difference you cannot see with your eye is a difference of 80% in metal content.
12 μm is the volume standard for household retail foil. 10 μm for discount and promotional packs. 15–18 μm for premium and heavy-duty positioning. In catering, 15 μm is the kitchen default and 18–20 μm where the foil meets heat or heavy loads. Specify ±5% tolerance as a minimum.
A 10 μm roll and an 18 μm roll are indistinguishable in a photograph, weigh differently by nearly 80%, and behave completely differently in the hand. Every complaint we see about "cheap foil that tears" traces back to a gauge decision made without understanding that.
Why thickness dominates cost
Foil is priced on metal content. At constant width and length, doubling the thickness doubles the metal per roll — so the price difference between gauges is not marginal, it is roughly proportional.
| Gauge | Relative metal content | Relative roll cost | Hand feel |
|---|---|---|---|
| 9–10 μm | 0.67 | Lowest | Very light, tears easily |
| 12 μm | 0.80 | Standard | The familiar retail feel |
| 15 μm | 1.00 | Baseline | Substantial, holds a fold |
| 18 μm | 1.20 | +20% | Stiff, premium |
| 20 μm | 1.33 | +33% | Heavy duty, board-like |
This is why two quotes for "300 mm × 50 m household foil" can differ by 30% and both be honest. One is 10 μm, the other is 15 μm. Neither supplier said so, because neither was asked.
Choosing by market, not by preference
10–11 μm
Discount chains, promotional packs, price-led markets. The roll must hit a shelf price point, and the customer is buying coverage rather than durability. Acceptable pinhole levels depend entirely on the mill's light-testing discipline — see pinholes.
12 μm — the default
Where most own-brand programmes sit. Thin enough to be competitive, thick enough to survive a dispenser edge and a fold. If you are launching an own-brand line without market data, this is the gauge that gives you the least to explain.
15 μm
Premium retail and the catering standard. Holds a crease, does not tear when pulled quickly, and reads as "good foil" to a user who has been sold 10 μm for years.
18–20 μm
Heavy-duty retail positioning, oven liners, grill work, large-format catering. At this gauge you are usually also moving to 3003 alloy for heat resistance — see the alloy guide.
Specify the thinnest gauge that survives your market's handling, not the thickest you can afford. In most price-sensitive markets, a well-made 12 μm beats a poorly-made 15 μm — because the failure customers complain about is tearing at the edge, and that is a slitting and gauge-consistency issue rather than a thickness one.
Tolerance: the part nobody quotes
A nominal thickness without a tolerance is not a specification. Standards allow variation across the width and along the length of a coil, and the size of that variation is what separates a good run from a marginal one.
At 12 μm, ±5% is ±0.6 μm — a range from 11.4 to 12.6. At 10 μm the same percentage is a narrower absolute band, which is why thin gauges are harder to hold and why the mill's capability matters more there.
How to check it yourself
- Micrometre at three points — head, middle and tail of the web, on several rolls. One measurement proves nothing.
- Measure the roll, not the sheet — unwinding distorts thin foil.
- Weigh a known area — mass per square metre divided by aluminium density gives an average thickness across the sample, which catches systematic under-gauge that a single-point measurement misses.
- Compare to the MTC — the mill test certificate should state the measured value and the tolerance band, not just the nominal.
Frequently asked questions
Is 10 μm too thin for retail?
No — it is standard in discount and price-led markets, provided the mill light-tests for pinholes and the slitting is clean. It becomes a problem when it is sold as a premium product, because the customer's first pull will tear it and the complaint lands on your brand.
Does thickness affect shelf life of wrapped food?
Indirectly. Barrier performance depends on pinholes more than nominal gauge — a 10 μm sheet with no pinholes outperforms an 18 μm sheet with a defect. This is why light-testing discipline matters more than the number on the box.
Can I mix gauges in one container?
Yes, and it is a sensible way to test price elasticity — same width and length, two gauges, two price points. It costs nothing extra in loading terms. See MOQ and mixed loading.
Sources
- EN 546-1 — Aluminium foil, technical conditions for inspection and delivery.
- Related: Pinholes in aluminium foil.