In Spain, onion calibres are measured with numbers.

The number-diameter ratio of the onion is as follows:

• From 100 mm and more.
• From 90 to 110 mm.
• From 80 to 100 mm.
• From 70 to 90 mm.
• From 60 to 80 mm.
• From 50 to 70 mm.
• From 40 to 60 mm.
• From 30 to 45 mm.

However, when exporting, we can adapt perfectly to the European calibration, if required by customers, which measures the millimetres of the diameter. Herein are the most common ones: 40-60 mm, 50-70 mm, 60-80 mm, 70-90 mm, 80-100 mm.