T-shirt design size for print on demand: 4500 × 5400 px explained
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If you sell shirts through print on demand, you have seen the number 4500 × 5400. Here is where it comes from, what the big platforms ask for, and what to do when your design is much smaller than that.
4500 × 5400 px is 15 × 18 inches at 300 dpi.
A digital image has no size in inches until you decide how many pixels go into each inch. That number is the resolution, written as dpi (dots per inch) or ppi. Print shops and POD platforms use 300 as the standard for crisp prints.
The math is one multiplication: pixels = inches × dpi. A 15 inch wide print area at 300 dpi needs 15 × 300 = 4500 pixels across, and an 18 inch tall one needs 5400 pixels. That is the whole secret of 4500 × 5400: it fills a 15 × 18 inch print area at full print quality.
| Print area | At 300 dpi | At 150 dpi |
|---|---|---|
| 15 × 18 in | 4500 × 5400 px | 2250 × 2700 px |
| 12 × 16 in | 3600 × 4800 px | 1800 × 2400 px |
| 10 × 12 in | 3000 × 3600 px | 1500 × 1800 px |
The big platforms ask for the same canvas, give or take.
- Printify describes a full-chest t-shirt file as 15 × 18 inches, 4500 × 5400 px, at 300 dpi, saved as a PNG with a transparent background and in the sRGB color profile.
- Amazon Merch on Demand asks for a 4500 × 5400 px PNG at 300 dpi for a standard t-shirt, with a transparent background and a file of 25 MB or less, according to seller guides published in 2024 and 2026. Amazon's own spec pages sit behind the Merch sign-in, so check the template in your account before you upload.
- Printful gives 12 × 16 inches as the usual t-shirt print area, 15 × 18 inches on select DTG products, and calls 150 dpi “the sweet spot” for its products. At 150 dpi, a 12 × 16 inch area needs 1800 × 2400 px.
The numbers differ a little, but a 4500 × 5400 px file at 300 dpi covers all three: it is big enough for the largest print area, and a platform with a smaller area scales it down without losing anything.
Your design doesn't have to fill the canvas.
The canvas is the largest area the printer can cover, not the size your design must be. A small chest logo or a design that is wider than it is tall sits inside the canvas, and everything around it is transparent, so nothing prints there.
Two habits help. Keep the background transparent rather than white, or a white box prints on a dark shirt. And leave a little room at the edges, so nothing important ends right where the printable area stops.
Changing the dpi number doesn't add detail.
Most image editors let you type 300 into a resolution box without changing anything else. The file now says 300 dpi, but it has exactly the pixels it had before. Printify's guide puts it plainly: you've relabeled the file, not rebuilt it. When the platform prints it at 15 inches wide, those few pixels are spread over the same 15 inches.
To check a file honestly, divide its width in pixels by the print width in inches. 4500 px over 15 inches is 300 dpi. 900 px over 15 inches is 60 dpi, and every pixel will show as a small square on the shirt.
A small design needs more than stretching.
Most designs don't start at 4500 × 5400. The four sample designs on this site are 896 × 1200 px JPEGs. At 300 dpi that is about 3 × 4 inches. To fill a 15 × 18 inch print area, the design has to grow 4.5 times.
Stretching it in an image editor makes each pixel 4.5 times bigger. Soft edges get softer, and the speckles around letters that JPEG compression leaves behind get printed as well. Some sellers upload the stretched file anyway and hope. The shirt shows it.
There are better ways, and which one fits depends on the art:
- Find the original file. If someone made the design for you, ask for the source: an AI, EPS, SVG, PDF or a large PSD. Nothing beats it.
- Redraw it as vector shapes. For flat-color art, such as lettering, logos and illustrations with a few solid colors, a vector redraw has smooth edges at any size, because it is made of shapes instead of pixels. That is what Optracy does: you upload the small file, fix the colors, and download a print PNG at 4500 × 5400 px.
- Upscale a photo. Photos and painted art with soft shading don't fit in a few flat colors. For those, an upscaler that adds pixels is the better tool. Check faces and text closely afterwards.
Optracy has three canvas sizes ready.
On the download page, one click gives you a print PNG at 300 dpi in one of three sizes:
- 4500 × 5400 px, 15 × 18 in, the standard full-front canvas
- 4000 × 4000 px, 13.3 × 13.3 in, for square print areas
- 3000 × 3600 px, 10 × 12 in, for smaller print areas
Your design keeps its proportions and the margin stays transparent. If a platform asks for something else, set your own width, height, units and dpi. The SVG, PDF and EPS of the same image are vector files, so they fit any size you need later.
When you don't need Optracy
If your file is already 4500 × 5400 px or larger and looks sharp when you view it at 100%, upload it as it is. And if your design is a photo, a redraw in flat colors would lose the shading that makes it work: use the largest original you have, or an upscaler made for photos.
Sources
Platform facts checked on Oct 6, 2026. Platforms change their requirements, so check their own pages before you upload.
- Printify, PNG file setup for t-shirts and DPI for printing
- Amazon Merch on Demand file requirements as summarized by Seller Sprite (2026) and Jungle Scout (2024)
- Printful, Everything you need to know to prepare the perfect printfile