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Image Crop & Resize Calculator

See exactly what to crop, resize or pad to fit your image to a target size without distortion.

Source image

JPEG, PNG or WebP · up to 10 MB · 50 million pixels · 32,768 px per side

Images, dimensions, previews and results stay in this browser tab. Nothing from this calculator is uploaded or automatically included in feedback. Refreshing clears entries.

Target

Your plan

Add source dimensions and a target to see the crop or padding plan.

How it works

  1. Upload a JPEG, PNG or WebP locally, or enter the source width and height in pixels.
  2. Enter target pixel dimensions or choose an aspect-ratio-only target. Custom ratios are supported.
  3. Compare Fill / Crop and Fit / Pad. Review edge removal, unused canvas and the preview.
  4. Copy the plan, then apply it in your preferred image editor. This calculator does not modify or download images.

A real example

Fictional image example: a 6000 × 4000-pixel source fitted to 1080 × 1350 (4:5) has two choices. Fill/Crop keeps a 3200 × 4000 crop, removes 1400 pixels from each horizontal edge, then resizes to 1080 × 1350. This removes 46.7% of the source width and area.

Fit/Pad preserves the whole image at 1080 × 720, leaving 315 pixels above and below on the 1080 × 1350 canvas. The image occupies 53.3% of that canvas. Neither method requires stretching.

Resizing, cropping and padding

Resizing changes pixel dimensions. Cropping removes part of the image; padding adds canvas around it. When the source and target aspect ratios differ, resizing directly to both target dimensions would distort the image. Fill keeps the largest source rectangle with the target ratio. Fit scales the complete source inside the target dimensions.

This image resize calculator plans geometry, not image quality. A larger output does not create additional detail, and a padded area need not have a particular color. No editing, compression, background generation or image download happens here.

Centered placement and whole pixels

The crop and padding are centered. Important subjects near an edge may be lost in Fill/Crop; use Fit/Pad or adjust the crop later in an editor. The preview is illustrative, with no handles or dragging.

Calculations preserve the exact ratio internally. When a dimension or centered edge split is fractional, the whole-pixel plan rounds the retained dimensions and gives an extra pixel to the right or bottom. These integer plans conserve total pixels but may slightly approximate the ideal aspect ratio. Displayed decimal geometry is rounded to one decimal place.

Frequently asked questions

Can I crop an image to an aspect ratio without knowing the output size?

Yes. Choose Aspect ratio only and a preset or custom ratio. Fill/Crop calculates the source rectangle and removed edges without inventing final output dimensions. Exact Fit/Pad padding pixels require target dimensions.

What is the difference between fit and fill?

Fill/Crop removes source edges to match the target ratio before resizing. Fit/Pad preserves the full source image and leaves unused canvas in the target rectangle.

Does it support portrait and landscape images?

Yes. Width and height are used as entered, without automatically rotating the target. Presets include both 16:9 and 9:16, 3:2 and 2:3, plus square, 4:5, 4:3, 21:9 and Custom.

Can I download the cropped or resized image?

No. This is a calculation and planning tool, not an image editor. Copy Results provides a text plan to use in your editor.

What upload and dimension limits apply?

JPEG, PNG and WebP uploads are limited to 10 MB, 50 million pixels and 32,768 pixels per side. Manual source and target pixel dimensions must be positive whole numbers up to 1,000,000 per side.

Are my image and dimensions uploaded?

No. Reading, previewing and calculations run in your browser tab. Images and calculation data are not sent to RST servers or automatically attached to feedback. Refreshing clears this session.

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