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Image Compressor

Compress JPG, PNG, and WebP images while keeping quality. Files stay in your browser.

100% Private — Your files never leave your device.

All processing happens in your browser. Nothing is uploaded to any server.

Drop files here or click to browse

Supports: JPG, PNG, WebP

Max 50MB per file

Lower = smaller file, more compression artifacts

%
10%100%

Resize wider images down to this width

px
Original4000px

Upload images to compress them

Results appear here instantly
Powered by CalcRun

How it works

Why Compress Images?

Large image files slow down websites, eat through mobile data, and take forever to upload or email. A single uncompressed photo from a modern smartphone can be 5-15MB — far more than needed for web use, social media, or email attachments.

How Our Compressor Works

This tool uses your browser’s built-in Canvas API to re-encode images at a lower quality setting. The entire process happens locally on your device:

  1. You drop or select images
  2. Your browser decodes the image pixels
  3. The Canvas API re-encodes them as JPG at your chosen quality
  4. You download the compressed result

No data leaves your computer at any point.

Choosing the Right Quality

Quality SettingBest ForTypical Size Reduction
90-100%Print, archival10-30% smaller
70-85%Web, social media50-80% smaller
40-65%Thumbnails, previews80-95% smaller
10-35%Extreme compression90-98% smaller

For most web use, 80% quality is the sweet spot — visually indistinguishable from the original while dramatically reducing file size.

Tips for Better Compression

  • Resize first: If your image is 4000px wide but will display at 800px, resize it down before compressing. Fewer pixels = smaller file.
  • Use the right format: Photos compress best as JPG. Graphics with flat colors and text compress best as PNG. WebP beats both for web use.
  • Batch process: Upload multiple images at once to compress them all with the same settings.

Real-World Examples

1

Product photos for an online store

Quality: 80 Max Width: 1,920

An e-commerce seller has 30 product photos averaging 8MB each (240MB total). At 80% quality with a 1920px max width, each image drops to 200-400KB — a 95% reduction. Total upload time goes from 20 minutes on slow WiFi to under 2 minutes, and pages load 5× faster for customers.

2

Wedding photos for email sharing

Quality: 85 Max Width: 2,400

A photographer needs to email 50 wedding photos to clients. The originals are 12MP (6MB each, 300MB total). At 85% quality and 2400px width, each file becomes 500KB-1MB. The entire batch fits in a single email without quality loss visible on screens.

3

Blog header images

Quality: 70 Max Width: 1,200

A blogger prepares images for WordPress posts. Original photos are 4000px wide at 5MB each. At 70% quality and 1200px max width, each compresses to 80-150KB — small enough for fast page loads while still looking crisp on all screens including Retina displays.

Frequently Asked Questions

How does image compression work?
Image compression reduces file size by removing redundant data. Lossy compression (like JPG) discards some visual information that's hard for the human eye to notice, achieving much smaller files. Lossless compression (like PNG) reorganizes data without losing any quality, but achieves less size reduction. Our compressor uses lossy JPG compression with a quality slider so you can choose the right balance.
Will compressing my images reduce their quality?
At quality settings above 70%, most people can't tell the difference between the original and compressed image. At 80-90% quality, the visual difference is negligible while file sizes can drop by 50-80%. Below 50% quality, compression artifacts (blurriness, banding) become more noticeable.
Is it safe to compress images online?
With CalcRun, yes — your files never leave your device. All compression happens in your browser using the Canvas API. No images are uploaded to any server. Most other online compressors upload your files to their servers for processing, which is a privacy concern for sensitive images.
What's the difference between JPG, PNG, and WebP compression?
JPG is best for photos and complex images — it compresses well but doesn't support transparency. PNG is best for graphics, logos, and images needing transparency — larger files but lossless. WebP offers the best of both worlds with smaller files than JPG and transparency support, but some older browsers don't support it.
How much can I reduce an image's file size?
Typical compression results: a 5MB photo at 80% quality often compresses to 500KB-1MB (80-90% reduction). Results vary based on image content — photos with lots of detail compress less than simple graphics. Adding a max-width resize (e.g., 1920px for web use) can reduce file sizes even further.

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