Will your artwork print sharp at this size?
Enter your magnet size and the tool works out whether your image has enough pixels per inch to print sharp, and flags it if it falls short.
How the checker works
What the calculation is doing
The checker takes the pixel dimensions of your image and the finished size you want to print, then works out how many pixels fall inside each inch of the printed magnet. That figure is the resolution, expressed as dots per inch (dpi): the number of printed dots packed into every inch of the finished piece. An image with plenty of pixels spread over a small magnet gives a high dpi; the same image stretched to cover a large one gives a low dpi, because the same pixels are being spaced further apart.
A worked example makes it concrete. A common promotional size is 90 × 55 mm, which converts to 3.54 × 2.17 inches. At 300 dpi that needs an image at least 1063 × 650 pixels. Feed in a smaller file and the tool will tell you the dpi it actually works out to at that size.
Why 300 dpi is the figure to aim for
300 dpi is the resolution most commercial printers set as their working minimum, because below it the individual dots of ink become visible to the eye at normal reading distance. A fridge magnet is handled and looked at close up, often held a few inches from the face while someone reads a phone number or a photo, so soft or pixelated print shows up more readily than it would on a poster viewed from across a room. Some printers will accept 250 dpi for larger magnets meant to be seen from further away; below that, text edges and photo detail typically start to look blurred. Confirm the minimum your printer works to before you send the file, since it can vary by press and by material.
Why bleed matters more as the magnet gets smaller
Bleed is the printed area that extends beyond the finished edge of the magnet, so that small variations in trimming do not leave a thin white line where the die has wandered off the cut line. Most magnet printers ask for 2–3 mm of bleed on each side, added to the finished size before you export the artwork. On a large sign that extra 2–3 mm is nothing; on a 65 mm magnet it is close to a tenth of the total dimension, which is why colour and background need to run right to the edge of the canvas. Inside the opposite edge sits the safe area, the inset zone (typically 3 mm in from the trim) where text and logos should stay clear of, so a small shift in cutting does not clip a name or a phone number.
The checker works from the pixel count and size you give it, so its answer is only as good as those two numbers; it cannot judge whether the photo itself is sharp, correctly exposed, or the right file for print. For bleed and safe area figures specific to a job, see what to specify when ordering printed promotional magnets.
What to do when your image falls short
If the checker reports a shortfall, you have three real options: crop the image down to a smaller finished size, resize it up in an editor, or go back for a bigger source file. Only one of those actually adds sharpness. The other two either trade size for quality or do nothing at all.
Cropping to a smaller finished size
Cropping raises the effective resolution because the same number of pixels is now covering a smaller printed area. An image that falls short at 150 mm across might clear 300 dpi comfortably once cropped to 90 mm. This is the option to reach for first if the composition can survive losing some of the edges, and it costs nothing to try because the checker will tell you straight away whether the crop has fixed it.
Resizing up in an image editor
Stretching an image to a larger pixel size in software such as Photoshop or GIMP does not create new detail. It interpolates, which means the software guesses at pixel values between the ones that already exist, and the result usually looks soft or blurred once printed. Upscaling can smooth over a very small shortfall, a few percent, but it will not turn a phone screenshot into artwork fit for an A5 magnet. Treat it as a last small adjustment.
When a bigger source image is the only fix
Where the shortfall is large, the pixel dimensions of the file itself are too low for the size you want to print, and no amount of cropping or resizing changes that. The only real fix is a higher-resolution version of the same image: a re-export from the original design file, a scan taken at a higher setting, or a photograph taken at the camera's full resolution. If that is not available, the practical choices are a smaller finished magnet size, a different image, or printing at the lower resolution and accepting that fine detail and small text will look soft.
Before you order, run the finished size and the source image back through the checker after any crop or resize, since a small change in either figure can move the result either side of 300 dpi. If you are ordering from a trade printer, confirm their minimum resolution and their bleed requirement directly with them, since some accept a lower dpi for large-format magnets than they do for small photo magnets.
Questions about artwork for fridge magnets
What file format should I send to a magnet printer?
Most magnet printers accept JPEG, PNG, PDF or TIFF, provided the file is large enough to print at 300 dpi (dots per inch, the print resolution most printers work to) at the finished size. A PDF is usually the safest choice for text-heavy artwork, such as a menu or calendar magnet, because it keeps type sharp regardless of the file's pixel dimensions. Photographs are normally fine as high-resolution JPEG or TIFF files. The accepted formats and any file size limit vary by supplier, so confirm with your printer before you finalise the artwork.
Should my artwork be in RGB or CMYK?
Printers work in CMYK (cyan, magenta, yellow and black, the four inks used in most print processes), while cameras, phones and screens produce images in RGB. Converting from RGB to CMYK usually shifts some colours slightly, particularly bright blues and greens, because the two systems can't reproduce exactly the same range. Supplying CMYK artwork from the start gives you a more accurate preview of the finished colour, but many printers will convert an RGB file for you as part of their process. Ask your printer which they'd rather receive.
How much bleed does a fridge magnet need?
Bleed is the printed area that extends beyond the finished edge of the magnet, so that small variations in trimming don't leave a pale strip at the border. For most magnet printers, 2 to 3 mm on each side is standard, meaning a 90 x 90 mm magnet is set up on a 94 to 96 mm square canvas before trimming. The exact figure depends on the printer's cutting equipment, so confirm the bleed allowance with your printer before you send the file.
What does 'safe area' mean, and how close can text go to the edge?
The safe area is the inset zone within the finished edge where no text, logo or other important detail should sit, kept clear in case the trim shifts by a millimetre or two. A typical safe area is 3 to 5 mm in from every edge, so on a 90 x 90 mm magnet your business name or phone number should sit at least that far from each side. Anything closer risks being cut off, or crowding the edge on a magnet that's trimmed slightly off-centre.
What does the resolution checker actually calculate?
It works out the dots per inch your image would print at, based on the pixel dimensions of the file and the finished size you enter, and runs entirely in your browser without uploading the file anywhere. That figure tells you whether the image has enough detail to print sharp at that size. It's a calculation from the numbers you give it, so it can only be as accurate as those numbers: enter the wrong finished size and the result will be wrong too.
My image passed the resolution check. Does that mean it will print correctly?
Resolution is one requirement among several. A file can sit comfortably above 300 dpi and still be rejected or reprinted if it's missing bleed, uses RGB colour where the printer needs CMYK, or has important text sitting inside the trim line. Treat a pass on resolution as one check cleared, and confirm bleed, colour mode and file format with your printer separately. See /blog/ordering-printed-promotional-magnets.html for what else printers typically ask for on a print-ready file.
Do I still need bleed and a safe area for a single custom photo magnet?
Yes. The same trimming tolerance applies whether a printer is cutting one magnet or several thousand, so a photo magnet made from a single holiday snap still needs 2 to 3 mm of bleed and a clear safe area around any cropped detail near the edge. Skipping it is more likely to show on a photo magnet than on a text-based one, because a face or a horizon line cropped a couple of millimetres off-centre is far more noticeable than a logo shifted the same amount. /blog/custom-and-photo-magnets.html covers cropping and framing choices specific to photo magnets.
Artwork Size and Resolution Checker
Enter your fridge magnet's finished size and the pixel dimensions of the image you intend to print. Nothing is uploaded, everything is calculated here in your browser as you type.
Effective print resolution
Document size to set up (including bleed)
Safe area (keep text, logos and phone numbers inside this)
Pixels needed for 300 dpi across the full bleed
How this is worked out
Dots per inch, dpi, is simply the pixel count divided by the physical size in inches, and 25.4 millimetres make one inch. This tool divides your image's pixels by the finished size converted to inches on each axis, and reports whichever axis comes out lower, because that weaker axis is the one that will actually be visible when the magnet is printed and trimmed.
300 dpi is the figure commercial print generally works to because at normal viewing distance it renders fine detail, small type and clean line edges without visible pixellation. Below that figure, detail starts to soften; well below it, the image is likely to look blurred or blocky rather than sharp.
Bleed exists because the trim at the cutting stage moves very slightly on every run. If the artwork stops exactly at the finished edge, that tiny movement can expose a thin white sliver of uncut stock. Extending the artwork past the trim line on every side means the cut still lands inside solid colour or image whichever way it drifts.
A safe area exists for the same reason, seen from the inside: anything important, such as text, a logo or a phone number, is kept a margin's distance back from the trim edge, so that if the cut drifts slightly inward it does not slice through wording or crop a logo awkwardly.
These figures are a check on the artwork you already have, worked out from what you have typed in. They are not a promise about what any particular printer requires: confirm bleed, safe margin and file specification with whoever is doing the printing before you send artwork.