Few three-letter acronyms cause as much form anxiety as DPI. A portal says upload a 300 DPI photo, a print shop asks for 300 DPI, and a website guide says 72 DPI is fine for screens. All of those can be true in context.
This guide separates pixels (what the image actually contains) from DPI metadata (how software suggests those pixels map to physical inches).
💡 Pro Tip
Need a practical resize? Use Resize Image for dimensions and Convert DPI when a form insists on a DPI tag.
Pixels are the real detail
An image that is 1200 by 1800 pixels has a fixed amount of detail. On a phone screen those pixels might cover a few inches of glass; on a poster the same pixels stretched large will look soft. You cannot invent true detail with DPI alone.
What DPI means
DPI (dots per inch) comes from print. PPI (pixels per inch) is the screen/document cousin. A useful formula: physical size in inches equals pixels divided by DPI. Example: 1200 pixels wide at 300 DPI is 4 inches wide in print.
Why web designers shrug at 72 DPI
Browsers display CSS pixels, not the EXIF DPI field. For web performance, optimize correct pixel dimensions and file size — not a magic DPI number.
Why printers care about 300 DPI
Ink on paper has no responsive layout. If you print a 300-pixel image three inches wide, you only have 100 pixels per inch — soft and blocky. 300 DPI is a common sweet spot for small photo prints and documents. A 2 by 2 inch photo at 300 DPI needs 600 by 600 pixels.
Forms that demand 300 DPI
Portals sometimes check the DPI metadata field, the pixel dimensions, the file size in KB, or all three. When a form is picky: set width and height first, set DPI to the requested value, then compress to the KB limit. Order matters.
72 vs 150 vs 300 cheat sheet
- Website and social: pixel width for layout; DPI mostly irrelevant
- Office laser docs: about 150 to 300 DPI for embedded images
- Photo lab prints: about 300 DPI at final print size
- Huge posters viewed at distance: lower DPI can be acceptable
DPI vs file size (KB)
DPI is not the same as kilobytes. A 300 DPI image can be 50KB or 5MB depending on pixel count and compression. Portals that want 300 DPI and under 100KB need resize plus compress together.
Bottom line
Pixels decide how much detail exists. DPI decides how those pixels map to physical inches and what fussy forms read in metadata. Web cares about pixels and file weight. Print and many official forms care about physical size plus adequate pixels, often labeled 300 DPI.
Once you separate those ideas, "set to 300 DPI" becomes a sizing problem you can solve in a few clicks with Resize Image and Convert DPI.
Topics
FAQFrequently Asked Questions
Is 72 DPI required for web images?
No. Web browsers primarily use pixel dimensions. 72 DPI is an old default, not a quality requirement for modern websites.
Does increasing DPI make a blurry photo sharp?
No. DPI metadata does not add real detail. You need enough pixels for the print or crop size you want.
What size is a 2x2 inch photo at 300 DPI?
2 by 2 inches at 300 DPI is 600 by 600 pixels.