How to Compress an Image to Under 30KB
30KB is a frequent file size cap on job application portals, university admission forms, government ID uploads, and HR systems. It is a tight target — most smartphone photos are 2–6MB straight out of camera — but entirely achievable with the right combination of resizing and quality settings. This guide gives you the exact steps.
Quick Answer
30KB is a frequent file size cap on job application portals, university admission forms, government ID uploads, and HR systems. It is a tight target — most smartphone photos are 2–6MB straight out of camera — but entirely achievable with the right combination of resizing and quality settings.
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Step-by-Step Guide
5 steps · takes under 1 minute
Start by resizing the image
Resize your image to the smallest dimensions that still meet the platform's display requirements. For a passport-style ID photo or avatar, 300×300px to 400×400px is usually enough. Use the Resize tool before compressing.
Convert to JPG
JPG is the most efficient format for photos under strict file size limits. If your image is PNG, convert it first — a 400×400 PNG can be 60–150KB, while the same image as JPG at 75% quality is typically 15–28KB.
Set quality to 70–75%
In the compressor, use 70–75% quality. For a 300–400px JPG this reliably hits under 30KB while keeping the image visibly sharp. Go down to 65% if needed.
Confirm the file size before uploading
Check the file size after download: right-click → Properties (Windows) or Get Info (Mac). If it is still over 30KB, trim the dimensions slightly or reduce quality to 65%. A 350×350px JPG at 70% is typically 16–24KB.
Upload and verify
Some portals show a file size error only after you click Submit. If rejected, reduce quality by 5% increments and re-upload until it passes.
Before vs After Compression
Typical result on a 1080×1080px product photo
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ImgToolkit runs entirely in your browser using the Canvas API. Your images are never sent to a server, never stored in the cloud, and never seen by anyone else. This makes it safe for sensitive documents, client work, medical imagery, and confidential screenshots.
Pro tip
Use 75–85% quality for web images — you get 60–80% smaller files with no visible difference at normal screen sizes.
Format & File Size Comparison
Same 1080×1080px photo processed four ways
| Format | Quality | File Size | Notes |
|---|---|---|---|
| PNG (original) | Perfect | 4.2 MB | No compression — too large for web |
| Compressed PNG | Visually identical | 1.1 MB | −74% — transparency preserved |
| JPG (85% quality) | Excellent | 310 KB | −93% · Best for photos |
| WebP (85%)BEST | Excellent | 205 KB | −95% · Recommended for web |
Based on a 1080×1080px photo. Results vary by image content and complexity.
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Compress to Under 30KB