Answer first
What this calculator tells you
Reduce a width and height to their aspect ratio and find the height at a new width. Resize an image, a video or a window without stretching it. Formula: Divide width and height by their greatest common divisor; new height = new width × height ÷ width. At the worked-example inputs, the ratio width part is 16. Holding every other input steady, moving width (pixels) from 1,536 to 2,304 moves the result from 8 to 88.
Transparent method
The formula
Resize an image, a video or a window without stretching it.
Worked example
Example inputs
How to interpret the result
An aspect ratio is width and height reduced to their smallest whole numbers. A 1920 by 1080 image divides by 120 on both sides to give 16 by 9, the shape of most screens and video. Once you know the ratio, any new width fixes the height: scale to 1280 wide and the matching height is 720, with no stretching or cropping.
At the worked-example inputs the ratio width part is 16. It rises with width (pixels); height (pixels) and new width (pixels) do not move it.
Password crack-time figures assume one specific guessing speed and no other weakness such as reuse, a data breach or a guessable personal pattern; a real attacker's actual speed and method can differ substantially. Subnet, transfer-time and storage figures are exact defined arithmetic, but a device, ISP or operating system may report a size or speed using a different unit convention (decimal or binary) than the one selected here.
Before you rely on it
What to check
Enter the full pixel dimensions of the original, not a rounded version. A width off by a few pixels produces an ugly ratio instead of a clean one.
The common error
Where people go wrong with aspect ratio calculator
Setting both the new width and the new height by hand. Only one of them is free, and choosing both distorts the picture.
Sensitivity evidence
How width (pixels) changes the ratio width part
Holding every other input at the worked-example value, moving width (pixels) from 1,536 to 2,304 moves the ratio width part from 8 to 88: a spread of 80, or 500% of the worked-example result.
| Width (pixels) | Ratio width part | Ratio height part | Height at the new width |
|---|---|---|---|
| 1,536 | 64 | 45 | 900 |
| 1,728 | 8 | 5 | 800 |
| 1,920worked example | 16 | 9 | 720 |
| 2,112 | 88 | 45 | 654.5 |
| 2,304 | 32 | 15 | 600 |
Every input, tested
Which input moves the ratio width part most
Of the 3 inputs, only width (pixels) moves the ratio width part: moving width (pixels) from 1,728 to 2,112 takes the ratio width part from 8 to 88, a swing of 500% of the worked-example figure. Height (pixels) and new width (pixels) do not change it at all.
| Input | Tested from | To | Ratio width part at each end | Swing |
|---|---|---|---|---|
| Width (pixels) | 1,728 | 2,112 | 8 to 88 | 80 (500%) |
| Height (pixels) | 972 | 1,188 | 160 to 160 | none |
| New width (pixels) | 1,152 | 1,408 | 16 to 16 | none |
Two variables at once
Ratio width part by width (pixels) and height (pixels)
Across the grid the ratio width part runs from 2 to 88. Moving width (pixels) from 1,536 to 2,304 shifts it by 32 at the middle column, and moving height (pixels) from 864 to 1,296 shifts it by 20 at the middle row, so width (pixels) is the bigger lever here.
| Width (pixels) \ Height (pixels) | 864 | 1,080 | 1,296 |
|---|---|---|---|
| 1,536 | 16 | 64 | 32 |
| 1,728 | 2 | 8 | 4 |
| 1,920 | 20 | 16 | 40 |
| 2,112 | 22 | 88 | 44 |
| 2,304 | 8 | 32 | 16 |
The highlighted cell is the worked example: 16.
Step by step
The worked example, input by input
| Input | Value used | What it means |
|---|---|---|
| Width (pixels) | 1,920 | Enter the width (pixels) used in this calculation. |
| Height (pixels) | 1,080 | Enter the height (pixels) used in this calculation. |
| New width (pixels) | 1,280 | The width you want to scale to. The height that keeps the ratio is calculated for you. |
| Ratio width part | 16 | |
| Ratio height part | 9 | |
| Height at the new width | 720 | |
Inputs, definitions and assumptions
Width (pixels)
Enter the width (pixels) used in this calculation. The prefilled worked-example value is 1,920.
Height (pixels)
Enter the height (pixels) used in this calculation. The prefilled worked-example value is 1,080.
New width (pixels)
The width you want to scale to. The height that keeps the ratio is calculated for you. The prefilled worked-example value is 1,280.
How to use this calculator
- 1Verify the inputs. Gather width (pixels), height (pixels) and new width (pixels) from your own documents; the prefilled values are examples.
- 2Save a baseline. The worked example puts the ratio width part at 16. Store your own version of it as Scenario A.
- 3Test one change. Start with width (pixels), the input with the biggest effect here: moving width (pixels) from 1,728 to 2,112 takes the ratio width part from 8 to 88, a swing of 500% of the worked-example figure.
- 4Check the extremes. At half the example width (pixels) (960) the ratio width part is 8; at double (3,840) it is 32.
People also ask
Frequently asked questions
How do you calculate aspect ratio?
Divide width and height by their greatest common divisor; new height = new width × height ÷ width. At the worked-example inputs the ratio width part is 16.
What does the aspect ratio result mean?
Resize an image, a video or a window without stretching it. At the worked-example inputs the ratio width part is 16. It rises with width (pixels); height (pixels) and new width (pixels) do not move it.
How much does width (pixels) change the ratio width part?
Holding every other input at the worked-example value, moving width (pixels) from 1,536 to 2,304 moves the ratio width part from 8 to 88, a spread of 80.
What are the limits of this aspect ratio calculator?
Password crack-time figures assume one specific guessing speed and no other weakness such as reuse, a data breach or a guessable personal pattern; a real attacker's actual speed and method can differ substantially. Subnet, transfer-time and storage figures are exact defined arithmetic, but a device, ISP or operating system may report a size or speed using a different unit convention (decimal or binary) than the one selected here. The tables on this page test width (pixels) only from 1,536 to 2,304; a value outside that range is not tabulated here.
If I double width (pixels) in the aspect ratio calculator, does the ratio width part double?
Doubling it from 1,920 to 3,840 takes the ratio width part from 16 to 32, which is 2.00 times the worked-example figure. So the result scales almost exactly in proportion. Halving it to 960 gives 8.
How much does height (pixels) matter in the aspect ratio calculator?
The worked example uses 1,080. The ratio width part does not depend on height (pixels); it moves the ratio height part from 81 to 99 instead when height (pixels) goes from 972 to 1,188.
How much does new width (pixels) matter in the aspect ratio calculator?
The worked example uses 1,280. The ratio width part does not depend on new width (pixels); it moves the height at the new width from 648 to 792 instead when new width (pixels) goes from 1,152 to 1,408.
Which inputs change the ratio height part in the aspect ratio calculator?
At the worked-example inputs it is 9. Width (pixels) takes it from 5 to 45 and height (pixels) takes it from 81 to 99.
Which inputs change the height at the new width in the aspect ratio calculator?
At the worked-example inputs it is 720. Width (pixels) takes it from 800 to 654.5, height (pixels) takes it from 648 to 792 and new width (pixels) takes it from 648 to 792.
Why does my hard drive show less capacity than what I paid for?
Manufacturers advertise storage using decimal gigabytes (10⁹ bytes), the SI-standard definition, while most operating systems report capacity in binary gibibytes (2³⁰ bytes) but label them "GB." A drive advertised as 1,000 GB shows as roughly 931 GiB once formatted, a real unit-definition gap , not missing storage.
What's the difference between a subnet mask and a wildcard mask?
A subnet mask marks the network portion of an address with 1 bits and the host portion with 0 bits; a wildcard mask is its exact bitwise inverse, used by some routing and access-control configurations instead of a subnet mask. Both describe the same /prefix, just inverted.
Does a bigger character pool always increase entropy more than adding length?
Not necessarily: going from a 62-character pool to a 94-character pool (adding symbols) raises entropy per character by less than one extra character of length does at most common pool sizes, because entropy scales with the logarithm of pool size but linearly with length.
Sources and evidence
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