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Upscale an image for print

Print it big without the pixels.

Enlarge a photo for the print size you want, then save it with the DPI you choose.

or drop it anywhere here · paste works too

FreeNo sign-upPhotos stay on your device

A kingfisher photo 170 pixels wide, enlarged as blocky pixelsBefore · 170 pxAfter · 4× sharper

Got a whole folder?

Queue up to 500 photos at once

Choose the paper and the density; the pixels each photo needs are worked out from them and the factor follows. DPI is a label, not detail — the file can carry a DPI tag, and that tag adds nothing to the picture.

Step 1 of 3 · Files

Drop one photo to print — or a folder to queue for printing.

A directory or a selection becomes a queue with one rule for every picture in it. A single photograph — dropped, picked or pasted — opens the review studio instead, with a before and after at 100%.

Pixels are read and worked in this tab; model files travel to it, never the other way.

What you are shown before anything runs

— and — minutes

files · tiles · milliseconds a tile, measured over real tiles cut from your own photographs a moment ago, and the name of the graph those numbers describe.

The blanks are blank on purpose. Nothing on this page quotes a duration it has not timed on the machine it is running on, which is why the estimate arrives after the set and not before it.

Model weights come from our model file server only when you press the control that names their size. Everything else — the runtime, the decoding, the inference, the archive — is served from this domain and executed here.

What this page does differently

A print needs a number of pixels, not a DPI. An A4 print at 300 DPI wants about 3,508 pixels on the long side; at 150 DPI, half that. The queue works that out for each photo from the paper and the density you choose, and enlarges only the ones that fall short.

The file can carry a DPI tag — written into the JPEG's JFIF header or the PNG's pHYs chunk after encoding, without touching a pixel — so print software lays it out at the intended size. The tag adds no detail, and this page says that first because “300 DPI” is the most misunderstood number in printing.

How sharp a print looks depends on how far away it is seen from, so the density you need falls as the print gets bigger. The table below is a rule of thumb, not a standard.

Viewing distance and density

A rule of thumb, not a standard: the density that looks sharp at the distance a print is usually seen from
PrintTypical viewing distanceDensity that looks sharp there
Up to A4Hand-heldAbout 300 DPI
A3 to A2Arm's length to 1 mAbout 150–200 DPI
Poster or canvasOver 1.5 mAbout 100–150 DPI

A4 at 300 DPI is about 3,508 × 2,480 pixels; A3 at 200 DPI is about 3,307 × 2,339. A photo that already has the pixels for the size and distance you need does not need enlarging at all, and the queue copies it through unchanged.

What it will not do

  • DPI is a label. Changing it alone changes nothing about the picture; only more pixels do, and above the model's 4× those pixels are a resample.
  • This page does not know your printer. It does not call a file print-ready; it tells you how many pixels a size needs and how many the file has.
  • WebP carries no DPI tag here. Save JPEG or PNG for print, or set the size in your print dialog.

Questions about this

Is my photo uploaded?
No. It is decoded and enlarged in this tab; the DPI tag is written in this tab too. Nothing is sent to a print service or anywhere else.
What does 300 DPI mean?
Three hundred pixels for every inch of paper. An 8×10 inch print at 300 DPI needs 3,000 × 2,400 pixels. The DPI number itself is only a label in the file that tells software how big to lay those pixels out.
Does changing DPI make the photo sharper?
No. A 1,200-pixel photo tagged 300 DPI prints at 4 inches; tagged 72 DPI it prints at 16.7 inches. Same pixels, same sharpness per pixel. Only more pixels make a bigger print sharper, and that is what the enlargement does.
How many pixels do I need for A4?
About 3,508 × 2,480 at 300 DPI, 2,806 × 1,984 at 240, and 1,754 × 1,240 at 150. The queue's print requirement does that arithmetic for every photo in a folder.
Do I need 300 DPI for a poster?
Usually not. A poster is seen from a metre or more, where 100–150 DPI already looks sharp. The viewing-distance table on this page is a rule of thumb for that.

Next on this site

Old prints going back to print start on the old-photos page, which cleans the scan first.

Photographic visual for Upscale Image For Print
Upscale Image For Print