US passport photo, a true 2x2 inch square

The square is not a suggestion

The 2 by 2 inch square is the most distinctive thing about the American format. Most of the world uses a portrait rectangle, so a photo taken for a UK, Indian or Schengen application cannot simply be cropped for a US one without the head landing outside the allowed range. The US frame is also tighter on the face: the head fills up to 69% of the height, compared with 51% for Canada.

Two measurements, not one

The United States is one of the few authorities that specifies both head height and eye position. The head must be 1 to 1 3/8 inches tall, and separately the eyes must sit between 1 1/8 and 1 3/8 inches from the bottom edge. Satisfying one while breaking the other is possible, which is why this tool checks and reports both.

The 240 KB problem

For online applications the file must be at least 600 by 600 pixels yet no larger than 240 KB. That is a genuinely tight budget, and it is the single most common reason an otherwise perfect photo is rejected by the upload form. Rather than guessing a compression level, the exporter binary-searches the JPEG quality until the file fits.

No glasses, since 2016

Glasses are not accepted at all. This includes reading glasses you might not think of as corrective eyewear. The only exception is a documented medical reason, which needs a signed statement from a medical professional submitted with the application. If you normally wear glasses, take them off and give your eyes a moment to adjust before the photo.