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KaiConvert
Local

Resize an image to exactly the size you need

Set a width and height, scale by percentage, or pick a preset — with the aspect ratio locked unless you say otherwise.

Drop an image here

or click to browse

Accepted: JPG, PNG, WEBP, GIF, BMP, AVIF

Try one of these

Processed locally. Your image never leaves your device.

Keep going without re-uploading

Your image stays loaded in the editor. Pick the next action and carry on.

Resizing sounds trivial until you have a specific target. A 4:5 Instagram portrait, a 1280×720 thumbnail and a 1200×628 link preview all need different treatment, and stretching an image into the wrong shape is the fastest way to make it look amateur.

This tool gives you the three things that actually matter: exact pixel control with an aspect lock, percentage scaling for “just make it smaller”, and a fit mode that decides what happens when your image and your target do not share a shape — stretch it, pad it, or fill and crop.

What you get

  • Exact pixels or percentage

    Type 1080 × 1350, or scale to 50%. Both routes lead to the same engine and the same predictable result.

  • Aspect ratio that stays locked

    Change the width and the height follows. Unlock it only when you actually want to distort the image.

  • Fit, fill or stretch

    When the target shape differs from the source, choose to pad with a colour of your choice, fill and crop the overflow, or stretch to fill.

  • Presets for the sizes people actually use

    Full HD, square, 4:5 portrait, 9:16 story, link preview, plus per-platform presets for Instagram, YouTube, TikTok, LinkedIn and marketplaces.

How it works

  1. 1

    Load your image

    The file is decoded locally into an ImageBitmap. Its natural dimensions appear in the panel as the starting point.

  2. 2

    Choose a target

    Enter a width or height, drag the percentage slider, or click a preset. The preview updates as you go.

  3. 3

    Pick a fit mode if the shapes differ

    Contain pads the image, cover fills and crops it, stretch ignores the aspect ratio. Contain lets you choose the padding colour.

  4. 4

    Export

    Download as PNG, JPEG or WebP — or keep going with crop, compress or text without re-uploading.

Why use KaiConvert

  • No upload for local tools
  • Works offline once the page is loaded
  • Cloud AI is always clearly labelled before you start

Frequently asked questions

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