3840x2160 aspect ratio: 16:9 (1.778:1)
3840 × 2160 reduces to 16:9. The greatest common divisor of 3840 and 2160 is 240, so 3840 ÷ 240 = 16 and 2160 ÷ 240 = 9. That is exactly 16:9.
Published · Updated · Sources last verified
At a glance
16:9
3840 × 2160 is exactly 16:9.
- Decimal
- 1.778:1
- Nearest named ratio
- 16:9, exact
- Orientation
- Landscape
- Pixels
- 8,294,400
- Megapixels
- 8.29
- Greatest common divisor
- 240
How 3840 × 2160 reduces
- 3840 = 1 × 2160 + 1680
- 2160 = 1 × 1680 + 480
- 1680 = 3 × 480 + 240
- 480 = 2 × 240 + 0
The last divisor, 240, is the greatest common divisor, so 3840 × 2160 reduces to 16:9. The method by hand is on the calculator page.
Crop or pad 3840 × 2160 to common ratios
Whole-pixel downscales
| Divide by | Size | Whole pixels | Nearest whole size |
|---|---|---|---|
| ÷2 | 1920 × 1080 | yes | same |
| ÷3 | 1280 × 720 | yes | same |
| ÷4 | 960 × 540 | yes | same |
| ÷5 | 768 × 432 | yes | same |
| ÷6 | 640 × 360 | yes | same |
| ÷8 | 480 × 270 | yes | same |
| ÷10 | 384 × 216 | yes | same |
Other listed sizes at 16:9
| Size | Scale from 3840 × 2160 | Whole-number scale | Pixel count |
|---|---|---|---|
| 1280 × 720 | 0.333 | yes, ÷3 | 0.111× |
| 1920 × 1080 | 0.5 | yes, ÷2 | 0.25× |
| 2560 × 1440 | 0.667 | no | 0.444× |
| 3840 × 2160this page's size | 1 | - | 1× |
Facts about 3840 × 2160
- 3840 × 2160 is exactly 16:9: 240 × 16 by 240 × 9.
- 3840 × 2160 divides into whole pixels by 2, 3, 4, 5, 6, 8 and 10, so a one-third size (1280 × 720) is still whole pixels.
- Among the other listed 16:9 sizes, it is a whole-number multiple of 1920 × 1080 (×2) and 1280 × 720 (×3); 2560 × 1440 (×0.667) is not a whole-number scale of it.
- Turned on its side, 3840 × 2160 becomes 2160 × 3840 (9:16).
- Cropped to 9:16, 3840 × 2160 keeps 31.6% (1215 × 2160); cropped to 1:1 it keeps 56.3% (2160 × 2160).
- 3840 × 2160 is 8,294,400 pixels (8.29 MP), 4 times the pixel count of 1920 × 1080.
Sourced notes
YouTube recommends 3840 × 2160 for video thumbnails, with a minimum width of 640 px.
Source: YouTube Help: video thumbnail requirements. Last verified 2026-10-05.
This size is one of the resolutions in YouTube's recommended 16:9 upload list.
Source: YouTube Help: recommended upload resolutions and aspect ratios. Last verified 2026-10-05.
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Aspect ratio 16:9 (1.778:1). Exact match for 16:9.
Aspect ratio
16:9
1.778:1
Exact match for 16:9.
- Width ÷ height
- 1.7778
- Height ÷ width
- 0.5625
- Shape
- landscape
Your numbers, worked
gcd(3840, 2160) = 240
3840 ÷ 240 = 16
2160 ÷ 240 = 9
3840 ÷ 2160 = 1.7778
Show how the gcd was found
- 3840 = 1 × 2160 + 1680
- 2160 = 1 × 1680 + 480
- 1680 = 3 × 480 + 240
- 480 = 2 × 240 + 0
Divide the larger side by the smaller, then divide the last divisor by the remainder until the remainder is 0. The last divisor is the gcd.
What each ratio would cut from 3840 × 2160
The largest centred crop at each ratio, best fit first. Crop rather than stretch.
| Ratio | Fit | Crop to | Lost |
|---|---|---|---|
| 16:9 | Exact | 3840 × 2160 | 0% |
| 1.91:1 | Trim height | 3840 × 2010 | 6.94% |
| 16:10 | Trim width | 3456 × 2160 | 10% |
| 2:1 | Trim height | 3840 × 1920 | 11.1% |
| 3:2 | Trim width | 3240 × 2160 | 15.6% |
| 21:9 | Trim height | 3840 × 1646 | 23.8% |
| 4:3 | Trim width | 2880 × 2160 | 25% |
| 5:4 | Trim width | 2700 × 2160 | 29.7% |
| 1:1 | Trim width | 2160 × 2160 | 43.8% |
| 32:9 | Trim height | 3840 × 1080 | 50% |
| 4:5 | Trim width | 1728 × 2160 | 55% |
| 3:4 | Trim width | 1620 × 2160 | 57.8% |
| 2:3 | Trim width | 1440 × 2160 | 62.5% |
| 9:16 | Trim width | 1215 × 2160 | 68.4% |
Solve the missing side
Pick a ratio, then enter the side you know.
Height is 2160. Size 3840 by 2160 pixels.
Size at 16:9
3840 × 2160
Height solved, in pixels.
Your numbers, worked
H = W × 9 ÷ 16 = 3840 × 9 ÷ 16 = 2160
Whole number, so no rounding is needed.
Pixel-exact: a 16:9 size needs the width to be a multiple of 16, and 3840 is 240 × 16.
Questions
What aspect ratio is 3840x2160?
3840 × 2160 is 16:9 (1.778:1). Dividing both sides by their greatest common divisor, 240, gives 16 and 9. That is exactly 16:9.
How do I resize 3840x2160 without distortion?
Keep the ratio at 16:9: new height = new width × 9 ÷ 16. Dividing both sides by 2, 3, 4, 5, 6, 8 or 10 keeps whole pixels, for example 384 × 216 at ÷10.
What is 3840x2160 cropped to 9:16?
A centered 9:16 crop of 3840 × 2160 is 1215 × 2160, which keeps 31.6% of the image. Padding it to 9:16 instead gives a 3840 × 6827 canvas with 4,667 px of bars. That canvas is rounded, not exactly 9:16: the exact padded side would be 6826.67 px tall. The smallest exact 9:16 canvas around it is 3843 × 6832.
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Apart from the sourced notes above, which devices use this size, and marketing names for it, are not covered: we did not verify a primary source for them, so this page sticks to arithmetic.