Formula
scale = target ÷ original · new dimension = original dimension × scale
A single scale factor is derived from the selected target and applied to both dimensions. Fit mode uses the smaller box ratio.
Image & screen
● Runs locallyImage Resize Dimensions
Calculate integer output dimensions without stretching an image. Choose a target width, height, percentage or bounding box, then control pixel rounding and whether a fit operation may upscale the source.
Example values
New image dimensions
Assumptions
- The original pixels are square and no crop is applied.
- Prevent upscaling caps the scale at 100%.
Pixel outputs must be integers, so the selected rounding rule can shift one dimension by a pixel.
Formula review
Formula v1.0.0
Reviewed 2026-08-03
CalcFlow engineering review
Image Resize Dimensions: Worked example
4032 × 3024 scaled to 1600 pixels wide uses 1600 ÷ 4032 = 0.396825. Applying that scale to the height gives 1200 pixels.
Frequently asked questions
Will the image be cropped?
No. This calculator preserves the full frame. Fit mode leaves unused space when the box ratio differs.
Why is one dimension rounded?
Raster dimensions must be whole pixels. The chosen rule converts the proportional decimal dimension to an integer.
Does upscaling improve quality?
The calculator only computes dimensions and does not infer or create missing image detail.