Guide

How to upscale AI art for print

Multiply the print size in inches by 300 to get the pixels you need at 300 PPI, then divide by your image’s pixels to get the upscale factor. A 1,024 × 1,024 px image upscaled 4× is 4,096 × 4,096 px, about 13.7 inches square at 300 PPI. Pick the smallest factor that reaches your size, upscale, and check the result at 100 % zoom before it goes to print.
Checked 24 Oct 2026 against MacnifyIt 1.3 (release notes, requirements, pricing).

The 300 PPI maths

pixels needed = inches × PPI. PPI means pixels per inch: how many image pixels land in each inch of paper. 300 is a common target for close viewing, and your print service states its own minimum, so check theirs. DPI is the printer’s dot density, a related but different number; image files carry PPI.
Pixels needed at 300 PPI
Print sizePixels at 300 PPI
8 × 10 in2,400 × 3,000
11 × 14 in3,300 × 4,200
16 × 20 in4,800 × 6,000
18 × 24 in5,400 × 7,200
24 × 36 in7,200 × 10,800
A4 (210 × 297 mm)about 2,480 × 3,508

Worked example: a 1,024 × 1,024 px image

1,024 × 1,024 px at 300 PPI
UpscalePixelsPrint size at 300 PPI
1× (no change)1,024 × 1,0243.4 × 3.4 in
2×2,048 × 2,0486.8 × 6.8 in
4×4,096 × 4,09613.7 × 13.7 in
8×8,192 × 8,19227.3 × 27.3 in
These are calculated widths, not print-quality guarantees. Generators change their output sizes between versions, so read it from your own file: in Finder, select the image and press Cmd-I, then look at Dimensions. Or enter it in the print size calculator.
Open the print size calculator

Which method: Exact, Clarity or Enhance (AI)?

Exact and Clarity use no AI. Enhance (AI) is the optional AI method. Contains AI-estimated detail.
Exact recalculates pixels from the pixels you already have, using Lanczos-3 and no AI. The larger file is the same picture, and soft areas stay soft. Choose it when the composition is approved, or when faces, hands, lettering or product details must not change.
Clarity does the same resampling, then sharpens the edges already in the picture, within a bound. It does not use AI either.
Enhance (AI) estimates additional detail on your Mac, with a slider for how much of the estimate you keep. It can make a soft or smooth AI render look fuller at a large size. Contains AI-estimated detail. Because it estimates, look closely at faces, text and fine patterns, and re-approve the result before printing.
A practical order: run Exact first and view it at 100 % zoom, and move to Enhance (AI) only if the image still looks too soft for the print size.

Steps in MacnifyIt

  1. Open the image, drop in a folder, or right-click files in Finder and choose MacnifyIt.
  2. Choose the factor from the table above (2×, 4× or 8×), or set the exact width or height you need.
  3. Choose Exact, Clarity or Enhance (AI). Contains AI-estimated detail.
  4. Compare the source and the result at 100 % in the compare view.
  5. Export as PNG, JPEG, TIFF or WebP. A job receipt records how each export was made.
MacnifyIt is US$29 once for one Mac, with 12 months of updates and no subscription. The free trial gives you 12 full-resolution exports, unlimited previews, no account and no time limit, enough to test a print-size job.
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Questions

How many pixels do I need to print a Midjourney image at 300 PPI?

Multiply the print width and height in inches by 300. An 18 × 24 in poster needs 5,400 × 7,200 pixels.

Can I upscale a ChatGPT image to 4K for print?

You can upscale any image file. 4K is a screen size (3,840 × 2,160 pixels is common); for print, work from inches × PPI as above.

Is 300 PPI always required?

No. It is a common target for close viewing. Large prints viewed from farther away often use less, and print services publish their own minimums. Ask your print service.

Will upscaling add detail the image does not have?

Exact and Clarity work only with the pixels already in the image. Enhance (AI) estimates additional detail. Contains AI-estimated detail. Check at 100 % zoom either way.

What is the maximum output size?

MacnifyIt caps output at about 400 megapixels, or about 200 megapixels when a 16-bit source is saved as 16-bit PNG or TIFF.

Try it on your own images.

12 full-resolution exports free. Unlimited previews. No account, no time limit.
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