Work out the print size of an image

Not in the way the question usually means, and no tool can. DPI is not stored in the pixels - it is a note in the file saying how large to print them. Changing that note from 72 to 300 makes the file claim it should print at a quarter of the size; it adds no detail and changes no pixel. What is real is the pixel count: 1800 x 1200 pixels prints 6 x 4 inches at 300 PPI, and that is true whatever the file's DPI tag says. This page works in pixels and physical size, which are the things that exist.

2481 x 3508 at 300 PPI, which is the number most print shops quote. At 200 PPI it is 1654 x 2339, and that is genuinely fine for something viewed at more than arm's length. The page works this out for any size and unit, and tells you whether the image you dropped in has enough.

It is a widely used industry convention, not a standard: 300 PPI and above is past what most people can distinguish in the hand, 200 is sharp for anything viewed from a foot away, 150 is fine for a poster, and below that is visibly soft up close. The important part is that the verdict is about the *size*, not the photograph. The same file is excellent as a postcard and poor as a poster, and nothing about it changed.

Bleed is extra image past the line where the paper will be cut, usually 3 mm, so that a millimetre of drift in the guillotine leaves ink at the edge rather than a white sliver. Commercial printers almost always require it for anything where colour runs to the edge; home printing does not use it, because a home printer leaves its own margin. The safe area is the same idea inverted: keep text a few millimetres inside the cut line, because the same drift can bite into it.

No, and the page warns you when you ask it to. Enlarging spreads the detail you have over a bigger area; the extra pixels are interpolated from neighbours rather than recovered from anything. It is sometimes still the right thing to do - a printer may want a specific pixel count - but it is not an improvement, and any tool that presents it as one is misleading you.

No. The dimensions are read by your browser on your device, the arithmetic happens in this tab, and an export goes through the same local pipeline as every other tool here. A content security policy the browser enforces prevents this page from sending your image to another domain.