UtilityKit

500+ fast, free tools. Most run in your browser only; Image & PDF tools upload files to the backend when you run them.

GIF Resizer

Resize animated GIFs to any width or height. Lock the aspect ratio or stretch — Lanczos resampling, palette-aware. Browser-only, no upload.

About GIF Resizer

GIF Resizer changes the dimensions of any animated GIF using ffmpeg.wasm — entirely in the browser, with no upload. The pipeline performs Lanczos resampling for sharp results on both upscales and downscales, and uses a fresh two-pass palette so colour quality survives the resize. Lock the aspect ratio (the default) and provide just one dimension, or unlock to stretch the GIF to exact width and height. The original frame timing, count and looping are preserved untouched. Use this whenever you need a GIF to fit a specific UI slot, social-media platform requirement, or chat-app size cap.

Why use GIF Resizer

  • Lanczos resampling for crisp results without softening or moiré
  • Two-pass palette so colours survive the resize
  • Aspect-ratio lock prevents accidental stretching
  • Original looping and frame timing fully preserved
  • 100% browser — your GIF never uploads
  • No watermark, no signup, completely free

How to use GIF Resizer

  1. Upload your animated GIF.
  2. Decide whether to lock the aspect ratio (recommended) or unlock for stretching.
  3. Enter a target width, height, or both. With ratio lock on, leaving one blank derives it automatically.
  4. Click 'Resize GIF' and wait for the two-pass encoder.
  5. Preview the resized result and click Download to save.

When to use GIF Resizer

  • Shrinking a 1080p screen-record GIF for a chat upload limit
  • Resizing a meme GIF to fit a specific message-board column width
  • Upscaling a small icon GIF for a higher-DPI display
  • Producing multiple sizes of the same animated banner for responsive design
  • Standardising GIF dimensions across a whole document or article
  • Hitting Twitter/Discord size caps with a precise pixel target

Examples

Shrink for chat

Input: 1920×1080 GIF, target width 640 px (height auto)

Output: 640×360 GIF preserving the 16:9 aspect ratio, ~12% of original size

Upscale icon

Input: 32×32 pixel-art GIF, target width 256 px (height auto)

Output: 256×256 sharp upscale via Lanczos for retina display use

Standardise banner sizes

Input: Various banner GIFs, all targeted to 728×90

Output: Uniform leaderboard-size animated banners ready for ad slots

Tips

  • Always leave the aspect-ratio lock on unless you have a deliberate reason to stretch — distorted GIFs look terrible.
  • Downscaling typically reduces file size by roughly the square of the scale factor: half-width is roughly a quarter the size.
  • Pair this tool with the GIF Compressor for the largest size wins — resize first, then compress.
  • When upscaling, prefer integer multiples (2×, 3×) for pixel-art GIFs to avoid blurring edges.
  • Check the resulting GIF on the actual target device — small thumbnails sometimes look fine on desktop but blur on phones.
  • If your input is extremely large, downscale to a draft size first, verify the result, then re-run on the original.

Frequently Asked Questions

Does my GIF leave my device?▾
No — ffmpeg.wasm runs locally in the tab. Nothing uploads to a server.
What is Lanczos resampling?▾
A high-quality interpolation algorithm that produces sharper results than bilinear or bicubic, especially on downscales. Used for both width and height changes here.
Why two passes?▾
Pass 1 builds an optimal palette from the resized frames; pass 2 encodes using that palette, which gives much better colour fidelity than re-using the original palette at a new size.
What does the aspect-ratio lock do?▾
When on, set just one dimension and the other is computed from the original aspect ratio so the GIF never distorts. When off, your width and height are used exactly as entered, which can stretch the picture.
Will the playback speed change?▾
No — frame delays are preserved exactly. Only spatial dimensions change.
Is upscaling lossless?▾
No — upscaling cannot invent detail. Lanczos produces a sharper-looking upscale than alternatives, but a 100×100 GIF cannot become genuinely sharp at 1000×1000.
What is the maximum size?▾
There is no server cap. Browser memory typically handles GIFs up to a few hundred MB; phones may struggle on very large inputs.
Why does it require Chrome or Edge?▾
ffmpeg.wasm requires SharedArrayBuffer, only available on cross-origin-isolated pages in Chromium-based browsers.

Explore the category

GIF Speed Changer Speed up or slow down any animated GIF using a precise multiplier. setpts filter via ffmpeg.wasm — palette-aware, browser-only, no upload. GIF Cropper Crop a rectangular region from any animated GIF. Set X/Y offset and crop dimensions in pixels. Palette-aware via ffmpeg.wasm. Browser-only. GIF Maker from Images Create animated GIFs from your own images. Drag, drop, set frame delay, loop and quality — all in the browser, no upload, no watermark. GIF Compressor Reduce animated GIF file size by lowering FPS, scaling dimensions and tuning palette. Two-pass palette encoding via ffmpeg.wasm — browser only. GIF to Video Converter Convert animated GIFs to MP4 (H.264) or WebM (VP9) video files. Smaller, smoother and far more efficient than GIF. Browser-only via ffmpeg.wasm. GIF Reverser Play any animated GIF backwards, or build a boomerang loop (forward + reverse). 100% browser via ffmpeg.wasm. No upload, no watermark.
GIF vs WebP vs MP4: Which Animation Format Wins on the Web? Animated GIFs are nostalgic but heavy. WebP and MP4 deliver the same motion at a fraction of the size. We compare file size, browser support May 2026 · 9 min

Glossary

Lanczos
A sinc-based resampling filter known for crisp results on both upscaling and downscaling.
Aspect ratio
The proportion of width to height. Locking the ratio prevents stretching.
Palette
The set of colours (max 256) available in a GIF frame. A fresh palette tuned to the resized frames preserves quality.
Resampling
Computing new pixel values when changing image dimensions; the algorithm choice (Lanczos here) determines sharpness.
Two-pass encoding
Running the encoder twice — once to analyse (palette), once to render (apply palette).
ffmpeg.wasm
Browser build of FFmpeg used for the entire resize pipeline locally.