What is the Label Roll Calculator?
Label printers and applicators have a maximum roll diameter. The label roll calculator works out how many labels fit on a roll from its outer diameter, core diameter, material thickness and label length plus gap, or the outer diameter needed for a given number of labels.
For sheet labels use the Label Size Calculator; to design shipping labels use the Shipping Label Generator.
How to use the Label Roll Calculator
- Enter outer diameter and core diameter.
- Enter material thickness (label + liner).
- Enter label length and gap.
- Read the number of labels per roll, or reverse the calculation.
Formula
Roll length = π × (D² − d²) ÷ (4 × thickness) · Labels = roll length ÷ (label length + gap)
Example
A roll of 100 mm diameter on a 25 mm core, 0.15 mm thick, holds about 49 m of labels: about 320 labels of 150 mm with a 3 mm gap.
Common core sizes
- 25 mm (1 inch): desktop printers
- 40 mm (1.5 inch): some desktop and mid-range
- 76 mm (3 inch): industrial printers and applicators
Related packaging and shipping tools
Packaging decisions are connected: the box size sets the volumetric weight, which sets the courier bill, and the carton size decides how many fit on a pallet or in a container. These related calculators help with the next step:
- Label size calculator: labels per box face and A4 sheet.
- Shipping label generator: printable 4 × 6 label.
- Barcode generator: Code 128, EAN-13 and UPC.
- QR code generator: links, WhatsApp and Wi-Fi.
- Packaging cost calculator: cost per box and product.
Frequently asked questions
How many labels are on a roll?
Enter the roll and label sizes to calculate.
What is the core diameter?
The inside diameter of the cardboard tube.
What thickness should I enter?
Label plus liner, often 0.12–0.18 mm.
Can I find the roll size for a number of labels?
Yes, switch to reverse mode.
Does it work for thermal labels?
Yes, for any roll of labels.
Is the Label Roll Calculator free to use?
Yes. The Label Roll Calculator on Custom Converter is completely free, with no sign-up, no daily limit and no watermark.
Does the Label Roll Calculator work on mobile phones?
Yes. It is built mobile-first and works on Android phones, iPhones, tablets and computers in any modern browser, with no app to install.