Half Letter at 300 DPI is 1650 × 2550 pixels

Half Letter (5.5 × 8.5 in) at 300 DPI is 1650 × 2550 pixels, which is 4.2 megapixels.

Portrait1650 × 2550 pixels
Landscape2550 × 1650 pixels
With 0.125 in bleed1725 × 2625 pixels
Megapixels4.2
Aspect ratio11:17
File size12 MB as uncompressed 8-bit RGB; a JPEG or PNG is smaller
Paper size5.5 × 8.5 in (139.7 × 215.9 mm)

The working

Pixels are inches multiplied by the resolution.

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 1725 × 2625 pixels.

Is your photo big enough?

To fill Half Letter at 300 DPI an image needs at least 1650 × 2550 pixels. Cropped to fill the sheet:

At 300 DPI the pixels of a print blend together from about 11.5 inches (29 cm) away. 300 DPI is the standard for print that is held in the hand: books, magazines, photo prints, business cards and flyers. At reading distance the eye can no longer pick out the pixels.

Half Letter at other resolutions

ResolutionPixelsWith bleedMegapixelsUncompressed
72 DPI396 × 612414 × 6300.24710 KB
96 DPI528 × 816552 × 8400.431.2 MB
100 DPI550 × 850575 × 8750.471.3 MB
150 DPI825 × 1275863 × 13131.13 MB
200 DPI1100 × 17001150 × 17501.95.4 MB
240 DPI1320 × 20401380 × 21002.77.7 MB
300 DPI1650 × 25501725 × 26254.212 MB
400 DPI2200 × 34002300 × 35007.521 MB
600 DPI3300 × 51003450 × 52501748 MB
1200 DPI6600 × 102006900 × 1050067193 MB

Other sizes at 300 DPI

Half Letter is a Letter page folded once, used for booklets, planners and invitations. See Half Letter in pixels at every resolution or everything at 300 DPI.