Image Crop Size Calculator
Find the largest crop dimensions that fit inside the source image at the target aspect ratio.
How to use Image Crop Size Calculator
1. Enter Source Width, Source Height, Target Aspect Ratio. 2. The source is not enlarged. Whole-pixel flooring can slightly change the requested ratio; this supplies dimensions without selecting a crop position or editing an 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?
The source is not enlarged. Whole-pixel flooring can slightly change the requested ratio; this supplies dimensions without selecting a crop position or editing an image.
How the calculation works
Fit the largest target-ratio rectangle inside the source; floor each derived pixel dimension. The source is not enlarged. Whole-pixel flooring can slightly change the requested ratio; this supplies dimensions without selecting a crop position or editing an 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: Source Width = 1920; Source Height = 1080; Target Aspect Ratio = "1:1". Result: 1080 × 1080 px.
Practical tip
Check the input labels and assumptions against the image crop size task before reusing the number.
Frequently asked questions
What exactly does Image Crop Size Calculator calculate?
Fit the largest target-ratio rectangle inside the source; floor each derived pixel dimension.
Which units or counting rules apply?
The source is not enlarged. Whole-pixel flooring can slightly change the requested ratio; this supplies dimensions without selecting a crop position or editing an 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.