Select film weight, thickness, roll length or roll width, then enter the three known quantities. The calculator preserves imperial and metric units and assumes a density of 0.91 g/cm³.
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BOPP Film Weight Formula
The calculator uses base units of mil for film gauge, feet for roll length, inches for roll width, and pounds for film weight. It assumes a BOPP density of 0.91 g/cm³.
- W = BOPP film weight in pounds
- G = mil gauge in mil, where 1 mil = 0.001 in
- L = roll length in feet
- X = roll width in inches
- K = conversion constant in lb per mil-ft-in, based on BOPP density of 0.91 g/cm³
Choose the value to solve for, enter the three displayed quantities, and select Calculate. For weight, length or width, choose the result unit. Use film-only weight, excluding the core and packaging.
If you enter metric units, the calculator converts them to the base units before applying the formula, then converts the result back to your selected output unit.
BOPP Film Weight Reference Values
The table below shows approximate roll weight in pounds for 1,000 ft of BOPP film at common widths and gauges.
| Mil Gauge | 12 in wide | 24 in wide | 36 in wide | 48 in wide |
|---|---|---|---|---|
| 0.7 mil | 3.31 lb | 6.63 lb | 9.94 lb | 13.26 lb |
| 1.0 mil | 4.73 lb | 9.47 lb | 14.20 lb | 18.94 lb |
| 1.2 mil | 5.68 lb | 11.36 lb | 17.04 lb | 22.72 lb |
| 1.5 mil | 7.10 lb | 14.20 lb | 21.30 lb | 28.40 lb |
These unit conversions are used when metric values are selected.
| Input Type | Conversion to Base Unit |
|---|---|
| Length | 1 m = 3.28084 ft, 1 cm = 0.0328084 ft |
| Width | 1 cm = 0.393701 in, 1 mm = 0.0393701 in |
| Weight | 1 kg = 2.20462 lb, 1 lb = 0.453592 kg |
Example Calculations
Example 1: Calculate BOPP film weight
You have a BOPP roll with a 1.0 mil gauge, 5,000 ft length, and 24 in width.
The approximate BOPP film weight is 47.34 lb, or about 21.47 kg.
Example 2: Calculate roll length
You have a 50 lb BOPP roll with a 1.2 mil gauge and a 20 in width.
The approximate roll length is 5,280.8 ft.
FAQ
What density does this BOPP film weight calculation use?
The calculation uses an assumed BOPP density of 0.91 g/cm³. This is a common approximation for BOPP film. Actual density can vary slightly depending on the film grade, additives, coatings, metallization, or lamination structure.
Why does the calculated roll weight differ from the actual roll weight?
The formula estimates film material weight only. A real roll may include a core, packaging, labels, splices, coating weight, adhesive layers, or moisture effects. If you are comparing against a scale weight, subtract the core and packaging weight when possible.
Is mil gauge the same as micron thickness?
No. Mil is an inch-based thickness unit. One mil equals 0.001 in, which equals 25.4 microns. To convert mil to microns, multiply mil by 25.4. For example, 1.2 mil is 30.48 microns.
