Aspect Ratio and Crop Size Calculator
Calculate a centered crop or a whole-image resize inside a target pixel box. Inspect retained area, edge trims, output dimensions and upscaling.
YOUR CALCULATION
Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Compare source and target width-to-height ratios. Crop the excess dimension symmetrically for an exact target fill, or scale both source dimensions by the smaller fit factor to keep the whole image.
Crop ratio=target width/target height; contain scale=min(target width/source width,target height/source height)
Worked example
A 4000×3000 source center-cropped to 16:9 retains 4000×2250 pixels, removing 375 pixels from both top and bottom. Resize that crop to 1920×1080. Containing the whole source instead gives 1440×1080.
Assumptions and input details
All dimensions are whole pixels from 1 to 10000000. Cropping is centered and axis-aligned. Ideal crop edges can be fractional source pixels, requiring resampling; an editor’s whole-pixel crop may differ. Contain output rounds downward to whole pixels and can slightly change the exact aspect ratio. A result with either contain dimension below one pixel is rejected. Upscaling is labelled and does not create image detail. This computes dimensions only, with no image upload, subject detection or actual editing.
References: Adobe image size and resampling
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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