Resize Image to 400×300 Pixels
Resize JPG, PNG or WebP images to exactly 400×300 pixels. Choose stretch, preserve & pad, or crop-to-fill, then export JPG or WebP.
Smart target workflow
Resize to 400 × 300px without guesswork
Batch up to 50 images, review the real output, then download images, ZIP or a combined PDF.
400 × 300 pixels at a glance
400 × 300 pixels is a landscape image 400 pixels wide and 300 tall: 120,000 pixels in total (0.12 megapixels), with a 4:3 aspect ratio (1.333:1). It is the shape of a phone photo held sideways, so landscape phone photos shrink to it without losing anything.
It is a small web image: sharp in a thumbnail or profile slot, too small to fill a phone screen. On this page our three test files came out at 13.2 KB to 62.8 KB as JPG and 2.8 KB to 55.1 KB as WebP.
Where 400 × 300 is asked for, and whether it fits
Instagram posts
Instagram keeps photos between 320 and 1080 pixels wide at their own resolution when the aspect ratio is between 1.91:1 and 3:4. 400 × 300 is 4:3, inside that range, so Instagram posts it uncropped at 400 pixels wide. On a phone feed that is just over a third of the 1080-pixel column, so it looks soft; 1080 × 810 is the same shape at full width.
WordPress medium size
WordPress core fits a medium copy inside 300 × 300 pixels and a thumbnail at 150 × 150. From a 400 × 300 upload WordPress creates a 300 × 225 medium copy and a cropped 150 × 150 thumbnail, so the 4:3 shape survives everywhere except the square thumbnail.
400 × 300 in numbers
Worked out from the pixel size. The crop rows assume the page's default "Crop to fill" setting.
| Measure | Value |
|---|---|
| Aspect ratio | 4:3 (1.333:1) |
| Total pixels | 120,000 (0.12 MP) |
| Uncompressed size (24-bit colour) | 351.6 KB |
| Print size at 300 DPI | 1.33 × 1 in (3.4 × 2.5 cm) |
| Print size at 150 DPI | 2.67 × 2 in (6.8 × 5.1 cm) |
| From a 4032 × 3024 landscape phone photo | No crop; scaled to 10% of its size |
| From a 3024 × 4032 portrait phone photo | Cropped to 3024 × 2268 (56% of the picture kept), then scaled to 13% |
| From a 1920 × 1080 screenshot | Cropped to 1440 × 1080 (75% of the picture kept), then scaled to 28% |
Sources: Instagram Help Center, "Photo resolution on Instagram" (https://www.facebook.com/help/instagram/1631821640426723); WordPress Developer Resources, "add_image_size()" (https://developer.wordpress.org/reference/functions/add_image_size/). Checked 2026-10-19. Platform rules change, and the form or service you upload to has the final say.
How to make a 400 × 300 image
Add your images
Drop one or more JPG, PNG or WebP files. All of them get the same size and format; you can move the crop for each one.
Check the crop
Sources with the same 4:3 shape are only scaled, so the preview shows the whole picture. Other shapes are cropped to fill; drag the preview to choose what stays.
Pick the format
JPG is accepted everywhere. WebP was smaller for most of our test files at this size, if the site accepts it; PNG keeps transparency but makes the largest files.
Download and check
The file name ends in -400x300, and the results panel shows the exact pixel size and KB so you can compare them with the form before uploading.
What this page produced from our test files
We ran three fixed test files through this page in headless Chrome 129.0.6668.29 on 2026-10-19, with the default "Crop to fill" setting. Sizes are the bytes of the downloaded files. The test files are generated from a fixed seed so anyone can repeat the run; they are not customer photos. WebP was smaller than JPG for all three files, by 12% to 83%.
| Test file | Format | Output | File size |
|---|---|---|---|
| Photo-style test image, 4032 × 3024 JPG (2.57 MB) | JPG | 400 × 300 | 13.2 KB |
| Photo-style test image, 4032 × 3024 JPG (2.57 MB) | WEBP | 400 × 300 | 5.6 KB |
| Screenshot-style test image, 1920 × 1080 PNG (24.3 KB) | JPG | 400 × 300 | 16.1 KB |
| Screenshot-style test image, 1920 × 1080 PNG (24.3 KB) | WEBP | 400 × 300 | 2.8 KB |
| Scan-style A4 test page, 2480 × 3508 JPG (3.4 MB) | JPG | 400 × 300 | 62.8 KB |
| Scan-style A4 test page, 2480 × 3508 JPG (3.4 MB) | WEBP | 400 × 300 | 55.1 KB |
Before you upload a 400 × 300 image
- 4:3 is the shape of most phone photos in landscape, so Crop to fill keeps the whole picture: nothing is cut off, it only gets smaller. A portrait (3:4) phone photo is the opposite case and loses 44% of its height.
- Requests for "400 by 300" sometimes mean 300 wide and 400 tall. Width always comes first in 400 × 300; if the form shows a tall frame, you need 300 × 400.
- At 300 DPI it prints at only 1.33 × 1 in (3.4 × 2.5 cm). It is a screen size; use a print-size page when you need paper.
Frequently asked questions
What aspect ratio is 400 × 300?
4:3, or 1.333 to 1. Any size with the same ratio, such as 800 × 600, has the same shape and can be resized to 400 × 300 without cropping.
How many KB is a 400 × 300 image?
In our tests, 13.2 KB to 62.8 KB as JPG and 2.8 KB to 55.1 KB as WebP. Without compression it would be 351.6 KB. Noise, text and fine texture make files bigger; flat graphics make them smaller.
How big does 400 × 300 print?
1.33 × 1 in (3.4 × 2.5 cm) at 300 DPI, or 2.67 × 2 in (6.8 × 5.1 cm) at 150 DPI. DPI only changes the print size, not the pixels, so the file is the same either way.
Next steps for your 400 × 300 file
Related image tools
Check the destination requirement
Upload rules change between services. MAXScanner prepares the file you request, but the receiving form or service is authoritative for its current pixel, format and byte limits.