DPI calculator: Photo 12 x 18

Use this calculator to find out how many pixels (resolution) an image should have to be printed at a certain size.

Print Dimensions

Net dimensions (no bleed)
304.8 mm x 457.2 mm = 139354.56 mm2 (diagonal: 549.49 mm)
30.48 cm x 45.72 cm = 1393.55 cm2 (diagonal: 54.95 cm)
12 inch x 18 inch = 216 inch2 (diagonal: 21.63 inch)
1 feet x 1.5 feet = 1.5 feet2 (diagonal: 1.8 feet)

Print Pixel Size

Dots-per-inch
Printer resolution = 300 dpi = 118 dots/cm
Printer pitch = 85 µm / micrometer (size of 1 pixel)
Net dimensions (no bleed)
3600 px x 5400 px = 19.4 megapixels
= aspect ratio 0.667

Some examples