The dimensions you need
Image resizer
Resize a JPG or PNG by pixels or percentage. Check the actual image before you download it.
Free · No upload · No account
Give your image the right dimensions
One JPG or PNG. Up to 20 MiB and 24 megapixels.
or drop one image here · files stay in this tab
Resize an image in three steps
- Choose one JPG or PNG. The preview follows the image’s orientation; your file stays on your device.
- Enter a width or height in pixels, or select a percentage. Keep aspect ratio on to preserve the image’s shape.
- Select Resize image, inspect the actual output, then download. Changing a setting removes the old download so it cannot be mistaken for your latest choice.
The output keeps the original format: JPEG stays JPEG and PNG stays PNG, including transparent pixels. There is no signup, watermark or upload.
Pixels, percentage and aspect ratio
Pixel dimensions describe width and height, not file size. With aspect ratio locked, a new width determines the height: new height = original height × new width ÷ original width. The result is rounded to the nearest whole pixel, with a minimum of one pixel per side.
| Original | Resize choice | Output |
|---|---|---|
| 4,000 × 3,000 | Width 1,600, ratio locked | 1,600 × 1,200 |
| 1,200 × 800 | 50% scale | 600 × 400 |
| 3,000 × 4,000 portrait | Width 600, ratio locked | 600 × 800 |
50% scale means half the width and half the height: one quarter of the original pixels. It does not mean the file will be half as many kilobytes.
Exact dimensions or proportional resizing?
With the ratio unlocked, both numbers are exact output dimensions. This can stretch or squash the image; it does not crop it or add borders. Keep the ratio locked when the shape matters. Enlargement requires explicit permission because extra pixels cannot restore missing detail.
Formats, quality and limits
Choose one static JPEG or PNG up to 20 MiB, 24 megapixels and 16,000 pixels on either side. The output has the same limits. Animated PNG, GIF, WebP, SVG, HEIC, CMYK JPEG and 16-bit PNG are unsupported; export a compatible static image first.
Resizing resamples pixels. JPEG downloads are re-encoded at high quality, which can lose detail even at unchanged dimensions. PNG keeps transparency, but reducing its dimensions still removes pixels. Files can become larger after resizing: this is not a target-KB compressor.
Camera orientation, including mirrored orientations, is applied before dimensions are calculated. Downloads do not retain source metadata or color profiles. Colors may differ from a color-managed editor; this is not a prepress or archival conversion tool. Check the downloaded image before using it.
Private by design
Processing runs in this tab. The image workspace has no analytics, image uploads or saved history. Reset clears the current tool state and releases its previews; it is not secure erasure. Browser tab restoration may preserve a session. Download only what you intend to keep.
Need a document instead?
Use JPG to PDF to arrange images on PDF pages, or explore Image Tools. Resizing here changes the image itself; choosing a PDF paper size is a different job.
Implementation references: MDN Canvas API and image decoding and orientation. Found a problem? Tell BiznTools.