Check the technical details of an image without uploading it. You can drag and drop an image onto the tool or choose one with the file picker, then see a thumbnail together with its file name, format and file size.
The details also include pixel dimensions, aspect ratio and megapixels. Once an image is loaded, the resize calculator lets you enter a new width or height and works out the other dimension in proportion.
Image Size Calculator
Check an image’s dimensions, file size and aspect ratio, then work out resized dimensions that keep the same proportions. Your image is read on your device only — it is never uploaded.
Drag and drop an image here, or use the file picker below.
| File name | — |
|---|---|
| Format | — |
| File size | — |
| Dimensions | — |
| Aspect ratio | — |
| Megapixels | — |
Resize calculator
Enter a new width or a new height — the other dimension is calculated automatically to keep the aspect ratio.
Privacy note: this tool uses your browser’s built-in file reading. The image never leaves your device and is not stored or sent to any server.
How to Use This Tool
- Drag an image into the drop area, or use Choose an image to select a file.
- Review the thumbnail and image details, including dimensions and file size.
- Note the aspect ratio and megapixels if you need them for a layout or upload.
- Enter a new width or a new height in the resize calculator.
- Use the paired dimension shown to resize the image in your chosen editor.
This tool inspects and calculates dimensions; it does not resize or download the image for you. It uses the browser’s built-in file reading, so the image never leaves your device and is not stored or sent to a server. Non-image files are rejected.
Looking for another tool? Browse our free online tools for calculators and counters.