Aspect Ratio Calculator
Enter the original width/height and a new width to calculate the ratio-preserving new height and the aspect ratio. Handy for resizing images and videos — all calculations happen inside your browser.
Enter the values to see the result.
How to use
- Enter the original width and height.
- Enter the new width you want.
- The new height that keeps the ratio and the aspect ratio are shown.
Frequently asked questions
How do I resize while keeping the aspect ratio?
Enter the original width and height and a new width; the new height is calculated as original height × new width ÷ original width, so the ratio is preserved.
How is the aspect ratio shown?
It is shown as the reduced ratio divided by the greatest common divisor of the original width and height. For example, 1920×1080 appears as 16:9.
Are the values I enter sent to a server?
No. All calculations happen only inside your browser, and the values you enter are never sent to or stored on any server.
Practical example and verification criteria
Aspect Ratio Calculator: First align number ranges and signs, integer, decimal, or fraction formats, and angle, length, or temperature units; avoid undefined inputs such as division by zero or a real square root of a negative number. Use the same unit for every length in geometry, and for percentages decide whether you need the base value or the change before entering values.
Aspect Ratio Calculator: For a quick check, start with 1920:1080 → 16:9 as a small input whose result relationship you can verify directly. Confirm that the input summary, units, and options match your intent before applying the tool to real values or a copy of the source; this reduces setup mistakes.
Aspect Ratio Calculator: Substitute the original values back into the displayed formula and use the inverse operation to see whether the input is recovered. Distinguish results with different dimensions, such as area and length. Compare reduced fractions, rounding, base-conversion digits, and Celsius/Fahrenheit reference points using small integers and boundary values to catch display errors.
Aspect Ratio Calculator · Work record: For real work, record the input conditions, selected options, and result together. Do not assume the same state will remain after a refresh or device change. Preserve important results separately using copy, download, a screenshot, or another method the page supports, then reopen them in the target environment.
Aspect Ratio Calculator · Error check: If an error or unexpected result appears, reduce the input, run again with default options, and then change one condition at a time. Recording error messages and boundary values helps distinguish format issues, unsupported cases, and browser resource limits, and prevents an empty result from being mistaken for success.
Aspect Ratio Calculator · Scope of use: Check the page guidance for browser processing versus server lookup, storage location, and supported scope. Use sensitive source material or secrets only when strictly necessary. High-impact work such as legal, financial, or medical decisions or changes to an operational system requires current authoritative information and a separate verification process.