Technical guide
Passport Photo Pixels and DPI: 2x2, 35x45 and 50x70 Explained
By Passport Photo Template Editorial Team | Published and reviewed June 29, 2026 | 9 minute read
Quick answer
At 300 pixels per inch, a 2x2 inch photo is 600x600 pixels. A 35x45 mm photo is approximately 413x531 pixels, and a 50x70 mm photo is approximately 591x827 pixels. Those conversions are useful for printing, but a digital application portal may require different pixel dimensions, file size and cropping rules.
Pixels, inches and millimetres describe different things
Pixels describe the width and height of a digital image. Inches and millimetres describe the physical size after printing. DPI, more precisely pixels per inch for an image, connects the two. A file can be 600 pixels wide and still print at many different sizes if the printer rescales it.
This is why looking only at the pixel dimensions is not enough. A 600x600 file printed at two inches is 300 pixels per inch. The same file printed at four inches is only 150 pixels per inch and is physically the wrong size for a U.S. printed passport photo.
The conversion formula
For inch-based sizes, multiply inches by the intended pixels per inch. For millimetres, divide the measurement by 25.4 and then multiply by the intended pixels per inch:
A pixel cannot be divided, so millimetre conversions are rounded to the nearest whole pixel. That one-pixel rounding does not change the intended physical measurement when the file is printed at the specified scale.
Common print conversions at 300 DPI
| Physical size | Approximate pixels | Common use |
|---|---|---|
| 2x2 inches | 600x600 | U.S. printed passport or visa photo |
| 35x45 mm | 413x531 | UK printed passport and many visa formats |
| 50x70 mm | 591x827 | Canadian printed passport format |
| 4x6 inches | 1200x1800 | Photo-lab print sheet |
The authority may describe a rounded metric equivalent. For example, the U.S. Department of State passport photo page describes 2x2 inches as 51x51 mm. For exact print math, our U.S. preset starts from two inches, which produces exactly 600 pixels at 300 DPI.
Why changing the DPI metadata does not add detail
Some image editors let you type 300 into a DPI field without changing the number of pixels. That changes an instruction stored in the file; it does not make a small or blurry image sharper. Real detail comes from the original camera capture.
If a face is already pixelated, enlarging the file to 600x600 only creates interpolated pixels. The U.S. Department of State says printed photos should be high resolution without visible pixels or printer dots. Start with a clear original rather than trying to rescue a thumbnail.
Digital upload rules are not print conversions
A digital portal may ignore DPI metadata and check pixel dimensions, aspect ratio, JPEG format, color space and file size directly. The U.S. visa digital image page, for example, specifies a square JPEG from 600x600 through 1200x1200 pixels, sRGB color and a maximum file size. GOV.UK digital photo guidance uses a different approach for online passport photos: a self-taken digital photo must be at least 600 pixels wide and 750 pixels high, and the user is told not to crop it because the application handles the crop.
Therefore, do not take a printed-photo conversion table and assume it is the upload specification. Read the instructions inside the exact application process.
Why a 4x6 sheet can hold six U.S. photos
A four-inch side holds two photos that are each two inches wide. A six-inch side holds three photos that are each two inches high. At 300 DPI, the same math is 1200 / 600 = 2 columns and 1800 / 600 = 3 rows. No scaling or stretching is required.
For 35x45 mm and 50x70 mm formats, the tool calculates the grid from the physical dimensions and centers the unused space. It never changes the aspect ratio simply to fit another copy.
How to verify the final output
- Select the correct application preset in the photo size tool.
- Open the official source link displayed beside the preset.
- Generate the single photo or 4x6 sheet.
- When printing, select the correct paper size and Actual Size or 100% scale.
- Measure the finished rectangle with a ruler.
- Check head size separately using the authority's definition.
Common pixel and DPI mistakes
- Assuming 600x600 always means two inches.
- Typing 300 DPI into a low-resolution file and expecting more detail.
- Using a 35x45 mm print crop for a digital portal that asks for an uncropped upper-body image.
- Letting a print service use Fit, Fill or automatic cropping.
- Confusing a photo's outer size with the required head height.
Related guides
For the U.S. head measurement, read our 2x2 print and head-size guide. For the handoff between files and paper, see digital versus printed passport photos.
Sources reviewed: U.S. Department of State passport photo and visa digital image pages, GOV.UK digital photo instructions, Canada passport photo requirements. Review date: June 29, 2026.