3:4 vs 4:5 Ratio Prints: The Difference That Matters
9x12 or 8x10? 3:4 and 4:5 look similar but don't interchange. Which sizes belong to each, the crop math between them, and why you need both files.
3:4 and 4:5 are the two ratios sellers mix up most, because the numbers look like siblings and the shapes differ by only 6%. But 6% is a person's forehead in a portrait or the top stem of a botanical print — buyers notice.
Which sizes belong to which
| 3:4 (0.75) | 4:5 (0.80) | |
|---|---|---|
| Sizes | 6x8, 9x12, 12x16, 18x24 | 4x5, 8x10, 16x20 |
| Shape | Slightly taller/narrower | Slightly squarer |
| Star size | 18x24 (big framed art) | 8x10 (the #1 frame in America) |
The test: short ÷ long. 9÷12 = 0.75 → 3:4. 16÷20 = 0.80 → 4:5. If a buyer asks "can I print the 8x10 file at 12x16?" the correct answer is "it'll work, but ~6% gets trimmed — use the 3:4 file instead," which is exactly why listings should include both files.
The crop math between them
Converting one master image into both ratios (keeping full width):
- Source at 4:5, cropping to 3:4 → you keep 93.75% of the height, lose 6.25%.
- Source at 3:4, cropping to 4:5 → you keep the full height but lose 6.25% of width (or crop height the other way).
Small, but it must come off the right edge. A face near the top of frame, a signature at the bottom, a moon in the corner — center-cropping blindly clips them. This is the entire reason to use a tool with a draggable focal point rather than batch-cropping in an export dialog. The Ratio-Pack Generator previews both crops side by side and lets you nudge each one independently.
Worked example: a portrait illustration at 3000x4000 px
Source is exactly 3:4 (3000÷4000 = 0.75).
- 3:4 file: untouched, 3000x4000 px → 9x12 prints at 333 DPI, 12x16 at 250 DPI, 18x24 at 167 DPI (list it as "up to 12x16 crisp").
- 4:5 file: crop to 3000x3750 px. The subject's hair brushed the top edge, so drag the crop down 120 px before exporting. Result: 8x10 at 375 DPI — flawless — and 16x20 at 187 DPI.
Two files, four minutes, and both of America's favorite frame sizes covered without a single stretched pixel.
Which one do you need more?
If you must choose: 4:5, because 8x10 outsells everything. But 18x24 is the most common "statement piece" size, and it's 3:4 — skipping it means losing the buyers who spend the most on frames. The full ratio system treats both as mandatory, alongside 2:3, 11x14, and ISO A. And whichever you export, check the DPI ceiling honestly — here's how DPI actually works.
Ratio-Pack Generator
Turn one image into every print ratio buyers ask for — 300 DPI, cropped in your browser. Free, instant, nothing uploads.