Image Resizer
Resize images by pixels, percentage or cm at a DPI, one at a time or in a batch.
Drop images here or paste them, or
Your images never leave your device
Processed in this browser · JPG, PNG, WebP, GIF, BMP, AVIF or HEIC · up to 50 at a time
For JPG and WebP. PNG stays lossless.
Resizes photos and images to exact pixel dimensions, a percentage of their size, or a print size in centimetres, millimetres or inches at a chosen DPI. Add one image or up to 50 at once and download them one by one or together as a ZIP. Images are resized in your browser and never uploaded.
How to use it
Pixels sets the width and height directly, from 1 to 30,000 px. With Keep aspect ratio on, type one side and the other follows each image's own shape, so a batch of portrait and landscape photos keeps every photo undistorted. With it off, both sides are fixed and Fit decides what happens when the shape differs: Crop to fill fills the size and trims the edges evenly, Fit inside shows the whole image and fills the rest with the background colour, and Stretch distorts it to the size. Presets fill in the sizes Instagram and YouTube recommend.
Percentage scales every image by the same factor, from 1% to 1,000%. Print size takes a size in cm, mm or inches and a DPI from 1 to 1,200 (default 300), and writes that DPI into JPG and PNG files.
Output format keeps each image's format, or saves all as JPG, PNG or WebP. GIF and BMP are saved as PNG and HEIC as JPG, since browsers cannot write them. Quality (default 90) applies to JPG and WebP; PNG is lossless. Limit file size keeps each file within a size range in KB by lowering the quality, or for PNG the number of colours, without changing the dimensions you chose.
Enlarging is allowed but adds pixels, not detail; the result says when an image was enlarged. Images keep their full size unless the browser cannot hold it: iPhone Safari stops at 16,777,216 pixels in area, and a larger result is scaled down to that, with a note.
The size of the image on show is listed under the size fields for reference, and each result shows over its original: drag the divider to compare them, and zoom to 100% or 200% to see detail at its real size. Options are remembered on this device, and Reset options puts them back to the defaults.
How print size and DPI work
A digital image has pixels, not centimetres. DPI (dots per inch) links the two: printed at 300 DPI, every inch of paper holds 300 pixels. Sizes in pixels are rounded to the nearest whole pixel, halves rounding up.
The DPI is also written into the file: the JFIF header of a JPG, and the pHYs chunk of a PNG, which stores pixels per metre (11,811 for 300 DPI). Print and layout software reads it to size the image on paper. WebP has no such field. The DPI does not change the pixels: a file at 72 DPI and one at 300 DPI with the same pixels look the same on screen.
Resized images are drawn afresh, so camera details such as the date, model and location are not carried over, and the orientation the camera recorded is applied to the pixels.
pixels = inches × DPI
pixels = centimetres ÷ 2.54 × DPI
pixels = millimetres ÷ 25.4 × DPI
Examples
A print size at 300 DPI
A 10 × 15 cm print at 300 DPI needs 1,181 × 1,772 px: 10 ÷ 2.54 × 300 = 1,181.1, rounded to 1,181. With Keep aspect ratio off and Crop to fill, a 4,000 × 3,000 px photo is trimmed at its sides to fit the 2:3 shape.
One side set, the other following
A 4,000 × 3,000 px photo with the width set to 1,080 px and Keep aspect ratio on becomes 1,080 × 810 px.
A square from a landscape photo
Resizing a 4,000 × 3,000 px photo to the Instagram square post preset, 1,080 × 1,080 px, with Crop to fill keeps the central 3,000 × 3,000 px and trims 500 px from each side.
Common print sizes in pixels
| Size | Pixels at 300 DPI | |
|---|---|---|
| Passport photo | 35 × 45 mm | 413 × 531 px |
| 4 × 6 in photo | 4 × 6 in | 1,200 × 1,800 px |
| 5 × 7 in photo | 5 × 7 in | 1,500 × 2,100 px |
| 8 × 10 in photo | 8 × 10 in | 2,400 × 3,000 px |
| A6 | 105 × 148 mm | 1,240 × 1,748 px |
| A5 | 148 × 210 mm | 1,748 × 2,480 px |
| A4 | 210 × 297 mm | 2,480 × 3,508 px |
Preset sizes
Each preset is the size the platform's own help page recommends. Instagram keeps photos up to 1,080 px wide, with aspect ratios from 1.91:1 (landscape) to 3:4 (portrait), and crops others. YouTube recommends 3,840 × 2,160 px thumbnails for videos and 2,160 × 3,840 px for Shorts.
Sources
- Image resolution of photos you share on Instagram — Instagram Help Centre
- Add custom thumbnails on YouTube — YouTube Help
Reviewed
Frequently asked questions
See also
- Image Compressor — to get a file under a size limit in KB, resizing only if needed.
- Crop Image — to cut a photo to an exact shape or size, choosing what to keep.
- Photo and Signature Resizer — to fit a photo or signature to an exam's exact size in pixels and KB.