Resolution lookup
3840×2160 Aspect Ratio: 16:9 Calculator
Find the 3840×2160 aspect ratio (16:9), see the reduction steps, and calculate resized dimensions without stretching.
3840 × 2160 is a 16:9 resolution commonly called 4K UHD. It contains 8,294,400 pixels, four times the pixel count of 1920 × 1080.
Resize With This Ratio — 16:9
Change either side. The other updates proportionally. Results show whole pixels and the exact value before rounding.
Exact height: 2160 px
How the ratio is calculated
3840 ÷ 240 = 16; 2160 ÷ 240 = 9. Dividing both sides by the same value preserves the proportions and gives 16:9. 240 is the greatest common divisor of these dimensions.
Height = width × 9 ÷ 16. Width = height × 16 ÷ 9. These formulas change size without changing shape. They do not crop or pad the source.
4K UHD: scaling and framing
Halving both dimensions gives 1920 × 1080 with the same shape. Do not confuse this size with 4096 × 2160: that wider frame simplifies to 256:135, not 16:9. Check the delivery specification before using a generic “4K” preset.
Ratio, resolution and units
A ratio compares width with height; it does not describe file size, compression or image quality. Enter both sides in pixels, inches or another matching unit. This calculator assumes square pixels for digital images. Video with a non-square pixel aspect ratio needs its display aspect ratio checked separately.
16:9 resizing examples
| Width | Exact height | Rounded height |
|---|---|---|
| 320 px | 180 px | 180 px |
| 640 px | 360 px | 360 px |
| 1080 px | 607.5 px | 608 px |
| 1920 px | 1080 px | 1080 px |
Decimal heights are displayed to four decimal places. Rounding can change the final ratio slightly. For an exact integer result, use dimensions that are whole-number multiples of 16:9.