The roll-length formula
A roll is an annulus: the outer cylinder minus the empty core. Dividing that material volume by web thickness gives approximate web length. With every dimension in millimetres, the result is in millimetres.
Web length = π × (outer diameter² − core diameter²) ÷ (4 × total caliper)
Labels before waste = web length ÷ (label length + gap)Worked example
For a 203 mm outer diameter, 76 mm core and 0.16 mm combined caliper, web length is approximately 173.93 m. A 100 mm label with a 3 mm gap has a 103 mm pitch: 1,688 theoretical labels, or 1,654 after 2% waste.
Measurements that affect the answer
| Input | Use this | Avoid this |
|---|---|---|
| Outer diameter | Finished roll diameter | Printer maximum capacity |
| Core diameter | Outside diameter of core | Core circumference |
| Caliper | Face stock + adhesive + liner | Face-stock thickness only |
| Pitch | Feed length + gap | Label width |
Why actual yield differs
Adhesive flow, liner variation, compression, winding tension, telescoping and start or end waste all change real yield. For a production commitment, compare the estimate with a counted roll or supplier specification for the same construction.
Frequently asked questions
Does label width affect labels per roll?
Not in a single-across roll-length calculation. Feed-direction pitch determines the count along the web.
Should the liner be included in caliper?
Yes. Enter the combined thickness of every layer wound around the core.
Run the calculation
Use your own measurements in the browser-based calculator. Inputs are processed locally and are not uploaded to LabelOps Lab.
Open the Label Roll CalculatorRelated guides
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