What is my aspect ratio?
Type a width and height to find the aspect ratio, or resize to a ratio from a new width or height. The aspect ratio calculator works as you type.
- Aspect ratio
- 16:9
A size of 1,920 × 1,080 has an aspect ratio of 16:9.
- Width
- 1,920
- Height
- 1,080
- Ratio as a decimal
- 1.7778
- Closest common ratio
- 16:9
Aspect ratio: 16:9. A size of 1,920 × 1,080 has an aspect ratio of 16:9.
How to calculate
Finds the aspect ratio of a width and height in lowest terms (1920 × 1080 is 16:9) with the closest common ratio, or resizes to a ratio from a new width or height.
Example with the default inputs (I want to Find the ratio, Width 1,920, Height 1,080): A size of 1,920 × 1,080 has an aspect ratio of 16:9.
Method: Aspect ratio = width : height, divided by their greatest common divisor; a new height is new width × H ÷ W (and a new width is new height × W ÷ H).
- Width and height are positive numbers in one unit, usually pixels; decimals are read exactly (2.39 is 239/100).
- Resizing keeps the ratio exactly, so a solved side may not be a whole number of pixels.
- The closest common ratio is the nearest of 1:1, 5:4, 4:3, 3:2, 16:10, 16:9, 1.85:1, 2:1, 21:9, and 2.39:1, flipped for a portrait size.
Worked examples
Each example is checked against the calculator on every build.
- I want to Find the ratio, Width 1,920, Height 1,080 gives Aspect ratio 16:9, Ratio as a decimal 1.777778, Closest common ratio 16:9.Source: ITU-R Recommendation BT.709-6, 1920 × 1080 at 16:9 (https://www.itu.int/rec/R-REC-BT.709)
- I want to Find the ratio, Width 1,366, Height 768 gives Aspect ratio 683:384, Ratio as a decimal 1.778646, Closest common ratio 16:9.
- I want to Find the ratio, Width 1,080, Height 1,920 gives Aspect ratio 9:16, Closest common ratio 9:16.
- I want to Resize to a width, Ratio width 16, Ratio height 9, New width 1,280 gives Height 720, Width 1,280, Aspect ratio 16:9.
- I want to Resize to a height, Ratio width 4, Ratio height 3, New height 1,000 gives Width 1,333.333333, Aspect ratio 4:3.
- I want to Find the ratio, Width 2.39, Height 1 gives Aspect ratio 239:100, Ratio as a decimal 2.39, Closest common ratio 2.39:1.
How it works
An aspect ratio compares a width with a height, written W:H.
Find the ratio. Type a width and a height. The calculator reads both exactly as decimals (2.39 is 239/100), divides width by height as an exact fraction, and writes that fraction in lowest terms as W:H. For whole numbers this is the same as dividing both by their greatest common divisor: 1920 × 1080 has a greatest common divisor of 120, so the ratio is 16:9.
Resize to a width, or to a height. Type the ratio W:H and the new width (or the new height). The other side keeps the ratio exactly:
- new height = new width × H ÷ W
- new width = new height × W ÷ H
The page also shows:
- Ratio as a decimal: width ÷ height (16:9 is 1.7778), shown to 4 decimals.
- Closest common ratio: of 1:1, 5:4, 4:3, 3:2, 16:10, 16:9, 1.85:1, 2:1, 21:9, and 2.39:1, where 21:9 stands for its standard value 64:27 (2.370), the one whose value (width ÷ height) is nearest to yours on a log scale: the smallest |ln(yours) − ln(common)|. For a portrait size (height more than width), the calculator compares height ÷ width instead and writes the result flipped, such as 9:16. A tie goes to the first ratio in the list.
Assumptions
- Width and height are positive numbers in one unit, usually pixels. They do not need to be whole.
- Resizing keeps the ratio exactly, so a solved side can have decimals. Answers show at most 6 decimals, or 6 significant figures for a value below 0.0001, rounded half up on the decimal value.
- A size beyond what a 64-bit float can hold gives no answer ("The size is too large or too small to show.").
Worked examples by hand
1920 × 1080. The greatest common divisor is 120: 1920 ÷ 120 = 16 and 1080 ÷ 120 = 9, so the ratio is 16:9. As a decimal, 1920 ÷ 1080 = 1.7778.
1366 × 768. The greatest common divisor is 2, so the ratio is 683:384 = 1.7786. The closest common ratio is 16:9 (1.7778).
1080 × 1920. The same numbers on their side: 9:16, a portrait screen.
16:9 at a width of 1280. New height = 1280 × 9 ÷ 16 = 720, so the size is 1280 × 720.
4:3 at a height of 1000. New width = 1000 × 4 ÷ 3 = 4000/3 = 1333.333333.
2.39 × 1. 2.39 is exactly 239/100, so the ratio is 239:100, and the closest common ratio is 2.39:1.
Other questions people ask
How do I calculate an aspect ratio?
Divide the width and the height by their greatest common divisor. For 1920 × 1080, the greatest common divisor is 120, so the ratio is 1920 ÷ 120 : 1080 ÷ 120 = 16:9.
How do I find the height for a width at 16:9?
Multiply the width by 9 and divide by 16. A 1280-pixel-wide video at 16:9 is 1280 × 9 ÷ 16 = 720 pixels high. For the width from a height, multiply by 16 and divide by 9.
Why is my screen not exactly 16:9?
Some sizes are rounded to whole pixels or to what the panel maker could build. A 1366 × 768 laptop screen is 683:384 exactly, which is 1.7786:1, very close to 16:9 (1.7778:1). The calculator shows 16:9 as the closest common ratio.
What are the common aspect ratios?
16:9 for HD and 4K video and most TVs and monitors; 4:3 for older TVs, iPads, and many cameras; 3:2 for 35 mm photos; 16:10 for some laptops; 1:1 for square posts; 9:16 for phone videos held upright; 1.85:1 and 2.39:1 for cinema; 21:9 (really 64:27, about 2.37:1) for ultrawide monitors such as 2560 × 1080. A 3440 × 1440 monitor, sold as 21:9, is 43:18, closer to 2.39:1.
What does an aspect ratio of 2.39:1 mean?
The width is 2.39 times the height. Written with whole numbers it is 239:100. The calculator reads decimals exactly, so a width of 2.39 and a height of 1 give 239:100.
Why is my resized height not a whole number?
The calculator keeps the ratio exactly. 1000 pixels high at 4:3 needs a width of 1333.33 pixels; round it to a whole pixel yourself (1333 or 1334), which changes the ratio very slightly.
Does the order of width and height matter?
Yes. Aspect ratios are written width first. A phone video held upright is 1080 × 1920, which is 9:16, the portrait form of 16:9.