Image Aspect Ratio Calculator

Calculate proportional image dimensions and see how an image will fit or crop to a target size without uploading it.

Image Aspect Ratio Calculator

Resize without stretching, or compare fitting and center-cropping an image into a target frame.

Private by design: calculations run in your browser. No image is needed, uploaded, or sent over the network.

Original image
Target frame

Enter 16 and 9 for 16:9, or 4 and 5 for 4:5. In this mode, the target frame uses your original image width; its height is calculated from the ratio. For a specific output size, choose Width and height.


Scale to target width

Proportional image size
Scale

Matches the frame width. Height follows the original image ratio, not necessarily the frame height.

Scale to target height

Proportional image size
Scale

Matches the frame height. Width follows the original image ratio, not necessarily the frame width.

Fit: show the whole image

Scaled image inside the frame
Scale
Empty space on each side
Cropped from each side
0 px — the entire image stays visible

Crop: fill the whole frame

Scaled image before cropping
Final output frame
Scale
Cropped from each side, after scaling
Equivalent crop in original-image pixels
Original-image region retained
Image area removed

All sizes are width × height. Fit and crop are centered, so opposite sides have equal spacing or cropping. Scaling may enlarge the image; this does not add detail. Results are rounded to two decimal places, but calculations use unrounded values. Pixel rounding in an image editor may shift a boundary by a pixel.

How to use the Image Aspect Ratio Calculator

Enter your original image’s width and height in pixels. Then choose a target aspect ratio, such as 16:9 or 4:5, or enter a specific target width and height. In aspect-ratio mode, the calculator uses the original image width as the reference frame width and calculates the corresponding frame height. Choose the dimensions option when you need an exact output size.

The proportional scaling results show two alternatives: matching the target width or matching the target height. Both preserve the original image’s proportions, so neither stretches or squashes it. They may not match both target dimensions when the original and target ratios differ.

Understand fit versus crop

Fit keeps the entire image visible inside the frame, leaving empty space when the ratios differ. Crop fills the frame completely, trimming overflow equally from opposite sides. The calculator reports the crop in scaled-image pixels and equivalent original-image pixels, helping you identify how much content will be lost.

Use these results to plan thumbnails, banners, product images, or presentation graphics before editing. Check the upscaling notice because enlarging an image does not create detail. Decimal results may need rounding in your editor. Everything runs locally in your browser; no image upload or network request is needed.