Aspect Ratio Reference
The common ratios as decimals, and the two formulas for resizing without distortion.
BFCBrilliance · bfcbrilliance.com/tools/aspect-ratio-calculator
Common ratios as decimals
- 16:9
- 1.7778 — video, most monitors, YouTube
- 4:3
- 1.3333 — older screens, many sensors, iPads
- 3:2
- 1.5 — most DSLR/mirrorless photos, 6x4 prints
- 1:1
- 1.0 — square
- 9:16
- 0.5625 — vertical video, Stories, Reels
- 21:9
- about 2.3333 — ultrawide monitors
- Cinema 'scope'
- about 2.39 — not the same as 21:9
- 5x7 print
- 1.4 — CROPS a 3:2 photo
- 8x10 print
- 1.25 — crops a 3:2 photo hard
The arithmetic
- Ratio
- width / height
- Height from a new width
- new width / ratio
- Width from a new height
- new height x ratio
- CSS padding percentage
- height / width x 100
- 16:9 padding
- 56.25%
- Pixels
- width x height
- ⚠ Double both dimensions
- FOUR times the pixels
- ⚠ Upscaling
- adds pixels, never detail
Size list for one image
| Where it is used | Ratio needed | Width | Height | Crops? |
|---|---|---|---|---|
Learn the decimal, not the colon
1.7778 against 1.5 tells you which is wider instantly. 16:9 against 3:2 does not. The decimal also copes with ratios that have no tidy whole-number form, which is most real images after any crop at all.
Print sizes are not one shape
A 6x4 is 1.5 and matches a 3:2 camera frame exactly. A 5x7 is 1.4 and an 8x10 is 1.25 — both of those crop your photo, and the 8x10 crops it hard. That is why the same image ordered in three sizes comes back framed three different ways.