What is 15 35mm on canon aps c in full frame?

15-35mm on APS-C (Canon) gives the view of 24-56mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 30-71mm
• Full frame: 24-56mm
• APS-C: 16-37mm
• APS-C (Canon) (yours): 15-35mm
• Micro Four Thirds: 12-28mm
• 1-inch: 8.9-21mm
• 1/1.3-inch: 6.7-16mm
• 1/1.7-inch: 5.2-12mm
• 1/2.3-inch: 4.3-10mm

Crop factors are by the sensor diagonal, rounded as they're usually quoted; a format with a different shape (4:3 against 3:2) frames a little differently across the width. More in the focal length converter.

Computed from the sensor sizes, not written by a model.