Resize an image online

Click to select or drag and drop your images

JPG, PNG, WebP, GIF · up to 20 images · 25 MB max per file

Processed in your browser: your images are never uploaded.

New size

Width (px)Height (px)

Aspect ratio locked: change the width or the height, the other side follows each image.

Output format

Quality85 %

How to use this calculator?

1. Add one or more images (JPG, PNG, WebP, GIF)
2. Choose the new size: in pixels, by percentage or a social media size
3. Choose the output format and quality
4. Download each image, or all of them at once in a ZIP

Quick answer

How do you resize an image without distorting it?

Keep the aspect ratio: change one side and work out the other with height = width × (original height ÷ original width). Example: a 4000 × 3000 px photo resized to 1200 px wide becomes 1200 × 3000 ÷ 4000 = 900 px high. For a fixed size (1080 × 1080 on Instagram), crop from the centre or add bands.

Format	Size in pixels
Instagram, square post	1080 × 1080
Instagram, portrait post	1080 × 1350
Story or Reels	1080 × 1920
LinkedIn, banner	1584 × 396
YouTube, thumbnail	1280 × 720

About the Resize Image

What is it?

The image resizer changes the width and height of your images. You can enter a size in pixels, a percentage, or pick a ready-made size for Instagram, Facebook, LinkedIn, X or YouTube, and process up to 20 images at once.

Why use it?

An image that is too large slows down a website, an email or an online form, and social networks crop photos badly when they do not have the right format. Resizing before you post keeps you in control of the framing, makes files lighter and speeds up page loading.

How does it work?

Each image is redrawn in your browser. With the aspect ratio locked, the missing side is calculated as height = width × (original height ÷ original width). For social media sizes, "fill" enlarges the image until it covers the frame and cuts the excess from the centre, while "bands" shrinks it so it fits whole. Large reductions are done in successive steps to keep the image sharp. No file is uploaded to a server.

Usage tips

Always start from the original image: enlarging a small image beyond 100% makes it blurry
On Instagram, the 1080 × 1350 portrait size takes up more space in the feed than a square
Use the "bands" mode for a logo or a visual with text, so nothing gets cut
Export as JPG or WebP at 80 to 90% quality for a light file, or as PNG to keep transparency
To make your images even lighter, run them through the image compressor afterwards

Embed this tool on your websiteFreeCopy this code into your website or blog: the tool shows up right on your page, free and without sign-up.

<iframe src="https://www.calculathor.fr/en/embed/resize-image/" title="Resize Image - CalculaThor" width="100%" height="650" loading="lazy" style="border:0;max-width:680px;border-radius:12px"></iframe>
<p><a href="https://www.calculathor.fr/en/resize-image/">Resize Image</a> by CalculaThor</p>
<script>addEventListener('message',function(e){if(e.origin!=='https://www.calculathor.fr'||!e.data||!e.data.calculathorHeight)return;document.querySelectorAll('iframe[src^="https://www.calculathor.fr/"]').forEach(function(f){if(f.contentWindow===e.source)f.style.height=e.data.calculathorHeight+'px'})})</script>

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