Image Resize Calculator
Calculate the proportional target height when an image is resized to a new width.
How to use Image Resize Calculator
1. Enter Original Width, Original Height, Target Width. 2. Positive whole pixel dimensions are required. The original aspect ratio is preserved subject to pixel rounding. This numeric tool does not resize an uploaded image. 3. Select Calculate or press Enter. 4. Select Copy result to copy the answer, or Reset to clear the form and result.
Why use this tool?
Positive whole pixel dimensions are required. The original aspect ratio is preserved subject to pixel rounding. This numeric tool does not resize an uploaded image.
How the calculation works
New height = original height × target width ÷ original width, rounded to a whole pixel. Positive whole pixel dimensions are required. The original aspect ratio is preserved subject to pixel rounding. This numeric tool does not resize an uploaded image. Counts and dimensions use the declared rounding convention; other numbers display up to three decimal places where applicable. Nonzero subsecond durations are labelled. Durations round to the nearest second; nonzero subsecond durations are labelled. File-size output units are decimal. Changing an input label does not convert filled values.
Example
Worked example: Original Width = 400; Original Height = 200; Target Width = 100. Result: 50 px.
Practical tip
Check the input labels and assumptions against the image resize task before reusing the number.
Frequently asked questions
What exactly does Image Resize Calculator calculate?
New height = original height × target width ÷ original width, rounded to a whole pixel.
Which units or counting rules apply?
Positive whole pixel dimensions are required. The original aspect ratio is preserved subject to pixel rounding. This numeric tool does not resize an uploaded image.
Does this inspect, change or upload my files?
This page calculates the entered values or text in the browser. Numeric image/media tools do not transform files. Check the worked example and stated counting basis; the result does not certify device, search-engine or accessibility outcomes.