Calcylator
Aspect Ratio Decimal

Aspect ratio as a decimal:
width ÷ height

Turn any screen, photo or video size into one decimal number so ratios are easy to compare.

Calcylator Editorial Team

Updated · 6 min read

What is an aspect ratio as a decimal?

The decimal aspect ratio is width divided by height. A 16:9 screen is 16 ÷ 9 = 1.778, so it is about 1.78 times as wide as it is tall. A value above 1 means landscape, 1 means square and below 1 means portrait.

One decimal is easier to compare than two numbers. 1920 × 1080 and 1280 × 720 both give 1.778, so they have the same shape even though the sizes differ.

The aspect ratio decimal formula

Aspect ratio as a decimal =ratio = width ÷ height
ratio:
decimal aspect ratio
width:
width in pixels or any unit
height:
height in the same unit
The calculator rounds to three decimals. Width and height must use the same unit, and height cannot be zero.

  • Width

    2560

  • Height

    1080

  • Divide

    2560 ÷ 1080

Aspect ratio decimal

2.370

The exact value is 2.37037, which is close to 21:9 (2.333) and is usually sold as ultrawide.

  1. Measure or look up the width and height in the same unit.
  2. Divide width by height.
  3. Compare the result with the common ratios in the chart.
  4. Round to three decimals.

Chart: common aspect ratios as decimals

Aspect ratios and their decimals
RatioTypical useDecimal
1:1Square social post1.000
5:4Some monitors and prints1.250
4:3Older screens, tablets1.333
3:2Photography1.500
16:9Widescreen video, TVs1.778
2:1Some phone screens2.000
21:9Ultrawide displays2.333
9:16Vertical phone video0.563

Using the decimal to resize images and video

To resize without stretching, keep the decimal the same. A 16:9 image 1,200 pixels wide must be 1,200 ÷ 1.778 = 675 pixels high. Use the ratio the other way and multiply the height by the decimal to find the width.

The decimal also tells you how much black bar to expect. A 1.778 video shown on a 1.333 screen leaves bars at the top and bottom, while a 1.333 picture on a 1.778 screen leaves bars at the sides.

Aspect ratios for social posts and video

Social platforms and video sites each accept particular shapes. A 1080 × 1350 portrait post has a decimal of 0.8, a 1080 × 1920 story is 0.563 and a 1920 × 1080 video is 1.778. Checking the decimal before you export avoids cropped edges.

The same check helps photographers. A 3:2 camera frame is 1.5, so printing it on a 5:4 (1.25) frame means cropping the long side. Knowing both decimals shows you that crop is needed before you order the print.

When two sizes give the same decimal, one is simply a scaled copy of the other. That is the idea behind resizing a picture proportionally.

Common mistakes with aspect ratios

  • Dividing height by width. That gives the inverse, so 16:9 would show as 0.563 instead of 1.778.
  • Mixing units, such as width in centimetres and height in pixels.
  • Rounding too early. 1.78 and 1.7778 give slightly different pixel sizes on a large image.
  • Assuming that equal decimals mean equal resolution. 1280 × 720 and 3840 × 2160 share a shape but not a size.

Common questions

What is 16:9 as a decimal?

16:9 is 1.778 as a decimal, because 16 ÷ 9 = 1.7777 and the calculator rounds to three places. It means the screen is about 1.78 times wider than it is tall, which is the standard widescreen shape.

How do I convert an aspect ratio to a decimal?

Divide the first number (width) by the second (height). For 4:3, 4 ÷ 3 = 1.333. For 21:9, 21 ÷ 9 = 2.333. The same method works with pixel sizes, such as 1920 ÷ 1080 = 1.778.

What is 4:3 as a decimal?

4:3 is 1.333 as a decimal. It is the shape of older television sets and many tablets. It is closer to square than 16:9, which is why the two do not fit each other without black bars.

What does an aspect ratio decimal below 1 mean?

A value below 1 means the shape is taller than it is wide. Vertical phone video at 9:16 is 0.563. A value of exactly 1 is a square, and anything above 1 is wider than tall.

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