# Calculate length of paper on a roll

## Calculation from diameter

Just fill in the top three boxes and read off the answer in the fourth box.

Enter the outside diameter of the roll in millimetres, the outside diameter of the core in millimetres
(likely to be about 95 mm for a 75 mm core), and the thickness in microns (likely to be between 50 and 200
for most uses, enter 0.05 mm as 50 microns). The result will be in metres.

## Calculation from weight

Enter the total weight of the roll in kilograms, the weight of the core (if known), the width in millimetres and the grade of the paper in grams per square metre, the result is the length in metres.

nib 2016-08-24