DPI Checker

Drop in an image, choose what you are printing, and see at once whether it will come out sharp: the pixels it gives each printed inch, a plain verdict, and the largest size it prints well. It judges by how the print will be looked at, because a business card held in the hand needs 300 pixels per inch and a banner across a room needs far fewer. It shows which part of the picture is trimmed when the shape does not match the sheet, allows for bleed if your printer asked for it, and reads the DPI label saved in the file so you can see why that label does not matter. No file to hand? Type the pixel size instead. Everything happens on your device, so the image is never uploaded.

How it works

DPI Checker is a web page that does its work on your own device. The file you choose is opened by your browser, changed there and saved from there; it is never sent to a server, so there is no copy of it anywhere to delete, no queue and no waiting for an upload. Most online tools of this kind send your file to their servers and work on it there, and many keep it for a while. This one does not. There is no account, no watermark and no limit on how often you use it, and the result downloads the moment it is ready.

What DPI really means for a print

A digital image is a grid of pixels, and that is all it is. It has no size in inches until someone decides how large to print it. Spread 3,000 pixels across 10 inches of paper and each inch gets 300 of them; spread the same pixels across 40 inches of banner and each inch gets 75. That number, the pixels you have for each printed inch, is what decides whether a print looks crisp or blocky. Printers call it DPI or PPI, and this tool works it out for the size you actually want.

Many files also carry a DPI number saved inside them, often 72 or 96. It is only a label that tells software how large to show the picture by default. It does not add or remove a single pixel, so changing it from 72 to 300 in an editor makes no difference to how the image prints. The checker shows you the label, and then ignores it, because the press will.

How many pixels per inch is enough

It depends on how far away the eye will be. The closer someone stands, the more detail they can see, and the more pixels each inch needs. These are the working rules used across the print trade; they are a guide rather than a standard, and your printer may ask for something different.

This is why a phone photo that would look soft as a magazine cover can make a perfectly good six-foot banner: nobody reads a banner from ten inches away.

Shape, trimming and bleed

A picture and a sheet of paper are rarely the same shape. To fill the sheet with no white strips, the picture is enlarged until both sides are covered and the overhang is trimmed away. The checker shows the trimmed part darker on your image, and works out the resolution from the side that has the fewest pixels to spare. If the sheet is upright and your picture is wide, it turns the sheet for you.

If your printer asks for bleed, the artwork has to run an eighth of an inch past the finished edge on every side, so that a cut which lands a hair off still shows ink rather than white paper. Tick the bleed box and that extra quarter inch each way is included in the sum.

What this tool does not do

• It does not make an image sharper. Enlarging an image in an editor invents the extra pixels by guessing, which softens it. The honest fixes are a smaller print or a larger original.
• It judges pixels only. A photo that is out of focus, heavily compressed or enlarged once already can have plenty of pixels and still print badly, so look at it at full size as well.
• It does not apply to vector artwork. Logos and text saved as vector shapes in AI, EPS, SVG and most PDF files have no pixels, and print sharp at any size.
• It does not open HEIC, TIFF, PSD or RAW files, which browsers cannot read.

What it does

• The real resolution at your print size, in pixels per printed inch
• A plain verdict: sharp, good, soft or too few pixels
• Judged by viewing distance: in the hand, on a wall or from a distance
• Common sizes built in, from 4 x 6 photos and business cards to posters and banners, in inches, feet, cm or mm
• Shows what gets trimmed when the picture and the sheet are different shapes
• Allows for 1/8 inch bleed when the printer asks for it
• The largest size the image prints well at each viewing distance
• Reads the DPI label saved in JPG and PNG files, and explains why it changes nothing
• Works from typed pixel dimensions when you do not have the file

Questions

How do I check the DPI of an image?

Open the image here and choose the size you want to print. The tool divides the pixels in the image by the inches of the print, which gives the real resolution at that size, and tells you whether it is enough. It also shows the DPI label saved inside the file, if there is one, although that label does not affect the print.

What DPI do I need for printing?

It depends on how far away the print will be seen. As a working rule of the print trade, anything held in the hand, such as photos, business cards and flyers, wants 300 pixels per inch and still looks good at 200. Posters and signs on a wall want 150. Banners seen from across a room or a street look sharp at 72, and large ones are often printed at less. Your printer may set its own requirement, which comes first.

My image says 72 DPI. Is it too low to print?

Not necessarily. The 72 is a label saved in the file that tells software how large to display it; it says nothing about how many pixels the image has. A 6000 x 4000 pixel photo labelled 72 DPI prints a sharp 20 x 13 inch poster. Check the pixels against your print size instead, which is what this tool does.

Can I change an image from 72 DPI to 300 DPI to make it print better?

Changing the label alone does nothing: the image has exactly the same pixels. Resampling it to add pixels makes the file bigger, but the new pixels are guesses made from the old ones, so the print is softer, not sharper. The real fixes are printing smaller or finding a larger original.

How big can I print a photo from my phone?

A 12 megapixel phone photo is 4032 x 3024 pixels. At 300 pixels per inch that is a sharp 13.4 x 10.1 inch print; at 150, right for a poster on a wall, it is 26.9 x 20.2 inches; and as a banner seen from a distance it can go to several feet. Open your photo and the table shows the sizes for your own image.

What resolution does a banner need?

Much less than people expect, because banners are read from a distance. 72 pixels per inch at the finished size looks sharp from across a room, so a 3 x 6 ft banner wants about 5184 x 2592 pixels, and 50 is usually still fine. Logos and text are best supplied as vector artwork, which has no pixels and stays sharp at any size.

What is bleed, and why does it change the answer?

Bleed is artwork that runs past the finished edge, usually 1/8 inch on every side, so that a cut landing slightly off still shows ink instead of a white sliver. It makes the printed area a quarter of an inch larger each way, so the image is stretched a little further. Tick the bleed box if your printer asked for it.

Why does it say part of my picture will be trimmed?

Because the picture and the sheet are different shapes. A phone photo is 4:3 and an 8 x 10 print is 5:4, so to fill the paper without white strips the picture is enlarged until both sides are covered and the extra is cut off. The darker area on the preview is what goes.

Does this work for PDF, AI, EPS or SVG files?

No, and it does not need to for most of them. Logos, shapes and text saved as vector artwork have no pixels and print sharp at any size. Only photos and other pixel images placed inside those files have a resolution, and you can check those here before you place them.

Is my image uploaded?

No. The image is opened and measured by your browser on your own device. It is never sent to us or to anyone else, and closing the tab clears it.

More

Privacy policy · Support · Changelog