Micron / Gauge / Mil Converter
Convert film thickness instantly between microns, mil, gauge, millimetres and inches — the units that vary by market and cause spec errors.
Inputs
Enter a thickness in any unit — the equivalents update instantly. 100 gauge = 1 mil = 25.4 µm.
Result
Gauge here is the plastic-film gauge (100 gauge = 1 mil), not a wire or metal gauge. See the Knowledge Base for material selection.
How to use itConvert any film-thickness unit
- Type a thickness into the box.
- Choose the unit it is in — micron, millimetre, mil, gauge or inch.
- Read every equivalent at once. The conversions update live as you type, so you can quote a spec in whatever unit your supplier or customer uses.
Why it mattersWhy film thickness units cause confusion
Film thickness is quoted differently across the industry and the world: microns in most of Europe and Asia, mil and gauge in North America, and occasionally millimetres or inches on engineering drawings. A "48 gauge" polyester and a "12 micron" polyester are the same film — but only if you know the conversion. Mixing them up leads to ordering the wrong material, mis-costing a job, or specifying a barrier that is off by a factor. A quick, reliable converter removes that risk and makes cross-market specifications unambiguous.
The mathsThe conversions
1 gauge = 0.254 µm
1 µm = 0.03937 mil = 3.937 gauge = 0.001 mm
Everything anchors to the inch: one mil is a thousandth of an inch, which is 25.4 microns, and film gauge divides that mil into a hundred parts, so 100 gauge equals 1 mil. That is why 48-gauge PET (0.48 mil) equals 12 microns, and 92-gauge (0.92 mil) equals 23 microns — the two most common polyester bases. Note this is plastic-film gauge, which is unrelated to the gauge numbers used for wire or sheet metal.
ReferenceCommon film thicknesses
| Micron | Mil | Gauge | Typical use |
|---|---|---|---|
| 12 µm | 0.48 | 48 | PET base for laminates |
| 23 µm | 0.92 | 92 | Thicker PET / print web |
| 25 µm | 1.0 | 100 | General film |
| 50 µm | 1.97 | 197 | Heavy sacks, lidding |
| 100 µm | 3.94 | 394 | Rigid-feel film, pouches |
RelatedWhere thickness feeds into decisions
Thickness drives material cost, barrier and machinability. Once you have the gauge right, the down-gauging calculator shows what a thinner film saves, the film usage calculator turns it into cost per pack, and the OTR / WVTR converter handles the barrier numbers.
FAQFrequently asked questions
How many microns is one mil?
One mil (one thousandth of an inch) equals 25.4 microns, and also equals 100 gauge. So a 1-mil film is a 25.4-micron film.
What is film gauge and how does it relate to microns?
Plastic-film gauge divides a mil into 100 parts: 100 gauge = 1 mil = 25.4 microns, so 1 gauge = 0.254 microns. For example, 48-gauge PET equals 12 microns. This is unrelated to wire or metal gauge.
What is 12 micron film in gauge and mil?
12 microns equals about 48 gauge and 0.47 mil. It is the most common polyester (PET) base thickness used in laminates.
Why do suppliers use different thickness units?
Convention varies by region: microns are standard in Europe and Asia, while mil and gauge are common in North America. Millimetres and inches appear on some engineering drawings. Converting between them avoids ordering or specification errors.
Is film gauge the same as wire gauge?
No. Plastic-film gauge is a direct fraction of a mil (100 gauge = 1 mil). Wire and sheet-metal gauges follow entirely different, non-linear numbering systems and must not be confused with film gauge.