Open an image above and it will tell you three things: how many pixels it has, what print size it claims, and how big you can actually print it before it goes soft. Type in the size you want and it will say whether that size works.
Nothing is uploaded. The file is read inside your browser, which is why the answer appears immediately and why a picture you would not email to a stranger is safe to open here.
What "resolution" means when something is going to be printed
A screen shows pixels. A press prints ink at a fixed density, measured in dots per inch. So the only question that matters is how many pixels you have to spread across the size you want:
- 300 dpi — what a press wants for something held at reading distance. A flyer, a menu, a business card, a page in a brochure.
- 150 dpi — the floor for large format, where the viewer is a step or two back. A pull-up banner, a poster on a wall.
- Below 150 dpi — the softness is visible to anyone who looks.
That is why an image's dpi on its own tells you almost nothing. A 3000-pixel-wide photo is 300 dpi on a 10-inch print and 30 dpi on a 100-inch one. It is the same file.
How to check the dpi of an image
Open it above. The number comes from the file's own header — the JFIF density in a JPEG, or the pHYs chunk in a PNG — and most pictures do not carry one at all.
That is normal, and it changes nothing. A resolution stamped in a header is a note the last program to save the file left behind; it is not a property of the pixels. Plenty of perfectly printable images say nothing, and plenty of unprintable ones confidently say 300. What decides whether your print is sharp is the pixel count against the size, and that is worked out for you either way.
Two numbers get ignored on purpose when they appear:
- 72 dpi is what a JPEG says when it means "I have an aspect ratio and no resolution".
- 25.4 dpi is a default that one common image library stamps into PNGs it saves without one.
Believing either would tell you your poster prints at a size no one intended.
How big can this print?
The tool answers this before you ask, at each of the three densities above, in millimetres, centimetres, inches or points.
This is the useful direction, and the one most people actually want. You rarely start with a size and hope; you start with a file somebody sent you and need to know what can be done with it. A 4000 × 3000 photo is a comfortable A4 at 300 dpi, a good A2 poster at 150, and a bad idea on a shopfront.
Will the size I want be sharp?
Type a width and a height and you get one of three answers — sharp, slightly soft, or blurry — with the resolution that size actually works out to.
The thresholds are printed on the page beside the verdict, so you can disagree with them. A pattern seen from ten metres survives numbers that would be unacceptable on a menu, and you know your job better than a web page does.
Resizing an image for printing
Making an image bigger does not add detail. Any tool that "upscales" is inventing pixels between the ones you have — sometimes convincingly, never with information that was not there. If this page says a file is too small for the size you need, the honest fixes are, in order:
- Find the original. The file that has been through a chat app twice is not the file the designer exported.
- Ask for a vector. Logos and type should almost never be pixels. A vector file has no resolution and prints sharp at any size.
- Print it smaller, or accept the softness deliberately rather than discovering it on delivery.
What this page did not check
It read resolution. It did not look at bleed, colour space, embedded fonts, overprint or trim size, and it makes no claim about whether a file is ready to print — only about whether the pixels are enough for the size.
That distinction matters more than it sounds. A file can be 600 dpi and still come back from the printer wrong.
When one file is not the problem
Checking a picture is the easy half. The expensive mistakes happen later, when a proof goes to a customer, comes back with three comments in an email, gets revised, and somebody approves the wrong version. That is the part Proofavo does: a proof link your customer opens without an account, comments pinned to the artwork itself, and a record of who approved which version and when.
If you want to mark up the image you just checked, the annotation tool opens in the same browser tab and works the same way — free, no sign-up, nothing uploaded.