Aspect Ratio Calculator
Height is calculated to match.
- 16:9
- Ratio
- 1.7778
- Decimal
- 720
- New height
- 2.07
- Megapixels
The aspect ratio calculator simplifies width and height to their lowest terms, converts to a decimal ratio, and calculates the matching height for any new width. It flags when that height is not a whole number, which is the point at which scaling starts to distort the ratio very slightly.
How it works
- Simplification divides both dimensions by their greatest common divisor: 1920 and 1080 both divide by 120, giving 16:9.
- The decimal ratio is width divided by height, 1.7778 for 16:9, 1.3333 for 4:3.
- Scaling multiplies the height by the same factor as the width: new height = new width × (height / width).
- Megapixels is width × height / 1,000,000, which is how camera resolutions are quoted.
The decimal form is often more useful than the simplified ratio for comparison. 1920×1200 simplifies to 8:5, which is hard to place against 16:9 until you see that its decimal is 1.6 rather than 1.778.
Examples
A standard HD frame
Width
1920
Height
1080
Result
Ratio 16:9 · Decimal 1.7778 · 2.07 megapixels
Both dimensions divide by 120. The decimal is the figure to compare against other ratios.
Scaling to a new width
Original
1920 × 1080
New width
1280
Result
New height 720
1280 × (1080/1920) = 720. A whole number here, because 1280 is a clean fraction of 1920.
A width that does not divide cleanly
Original
1920 × 1080
New width
1000
Result
New height 562.5, flagged as non-integer
Rounding to 562 or 563 changes the ratio slightly. Unavoidable when scaling to an arbitrary width, but worth knowing rather than discovering as a one-pixel gap in a layout.
Frequently asked questions
Why does my scaled height come out as a fraction?
Because the new width is not a clean multiple of the original ratio. 1920×1080 scaled to 1000 wide needs a height of 562.5, and rounding either way shifts the ratio by a fraction of a percent. Choosing a width divisible by 16 avoids it for 16:9 content.
What is the difference between 16:9 and 16:10?
About 11 percent more vertical space in 16:10, which is 1.6 against 1.778. 16:10 was common on monitors in the late 2000s and has returned on some laptops, because the extra height suits documents and code better than video.
Does a higher megapixel count mean a better image?
Only for detail at large sizes. Megapixels tell you the total pixel count and nothing about sensor size, lens quality or dynamic range, all of which matter more for how an image actually looks.
How is this different from the general ratio calculator?
This one is specific to pixel dimensions, so it adds megapixels and the scale-to-new-width calculation. The general ratio calculator handles three or more parts and answers share-of-total questions instead.