4 × 6 inch photo at 600 DPI is 2400 × 3600 pixels

The working

Pixels are inches multiplied by the resolution.

• Width: 4 in × 600 = 2,400, which rounds to 2400 pixels.
• Height: 6 in × 600 = 3,600, which rounds to 3600 pixels.

Bleed is extra image past the trim line, so that a cut that lands slightly off still leaves ink to the edge. Print shops usually ask for 0.125 in on every side of a US size, which makes the file 2550 × 3750 pixels.

Is your photo big enough?

To fill 4 × 6 inch photo at 600 DPI an image needs at least 2400 × 3600 pixels. Cropped to fill the sheet:

• A 12 megapixel phone photo (4000 × 3000) gives 667 DPI: enough.
• A 24 megapixel camera photo (6000 × 4000) gives 1,000 DPI: enough.
• A 48 megapixel photo (8000 × 6000) gives 1,333 DPI: enough.

At 600 DPI the pixels of a print blend together from about 5.7 inches (15 cm) away. 600 DPI is used for line art, small text and scans that will be enlarged. It is also the native resolution of many office laser printers.