Compress Image to 20 KB
20 KB is one of the most common upload ceilings on application and exam portals. Set it once and the tool finds the best quality that fits.
Original
Compressed
Leave empty to use quality slider. We'll automatically find the best quality to hit your target size.
Compress an image to 20 KB without sending it anywhere
This page does one job: get your file to 20 KB or less. The target-size field is already set to 20, so you only have to pick a file. The compression runs inside your browser — nothing is uploaded and no account is needed.
Where the 20 KB limit comes from
Signature and photograph uploads on many exam and job application portals sit in the 20 KB to 50 KB range. Some university and scholarship forms reject anything above 20 KB for a scanned signature. Directory and CRM avatar fields frequently enforce a 20 KB limit to keep record previews light.
Why the file keeps going over 20 KB
Uploading a straight-from-phone photo (often 3 MB or more) and expecting quality alone to bridge the gap. Scanning at high DPI: a 300 DPI scan of a signature is far too many pixels for 20 KB. Forgetting that the target-size box only applies to JPG and WebP output.
Private by design
There is no upload step and no server round trip. The image is decoded, re-encoded and offered back to you as a download, all inside the page. That also means it keeps working when a locked-down portal or an inbox is the only thing you have access to.
What this page does — and what it does not
A 20 KB target is a narrow job. Here is exactly what is, and is not, on offer.
Hits an exact 20 KB target
The target is pre-filled. The tool searches quality until the file lands at or under 20 KB.
Nothing is uploaded
Decoding, re-encoding and download all happen inside the page. No server round trip, no account.
Keeps your pixel dimensions
Target-size mode only tunes compression quality. It will not shrink the image for you — resize first if the pixel count is the problem.
One image at a time
This is a single-file page. For a whole folder, use the Bulk Image Processor instead.
How to compress an image to 20 KB
Step 1
If it is a scan, re-scan at a lower DPI or crop tightly to the signature area first.
Step 2
Use the Image Resizer if the long edge is over 1200 px — 800–1000 px is usually enough for a form photo.
Step 3
Upload here, leave the target at 20 KB, and choose JPG output.
Step 4
Compress and check the reported size. Aim a little under the limit to leave headroom for server-side checks.
Compressing to 20 KB in Detail
Note on mechanics: the tool re-encodes your file at up to eight JPEG/WebP quality levels between roughly 10% and 95% and keeps the smallest result that lands at or under 20 KB. It never changes pixel dimensions. 20 KB is where cropping starts to matter more than quality: removing empty background buys more than any further compression step.
The exam and job portal convention
The 20 KB figure is a tradition rather than a technical requirement. Application portals were built when submissions arrived over slow links, and the number has been copied from form to form ever since. Because it is enforced by a simple byte comparison, it is unforgiving: a file at 20.4 KB fails exactly as hard as one at 2 MB. That is why the useful skill here is landing slightly under, not exactly on.
Why a scanned signature is the hard case
A signature is mostly pen strokes on white space. At 300 DPI an A4-page scan is roughly 2480×3508 px — about 8.7 million pixels. Compressing that to 20 KB leaves about 0.002 bytes per pixel, which is not enough to represent strokes as anything but mush. Crop to the signature box and scan at 150 DPI instead, and the same 20 KB looks sharp.
Checklist before you upload for a 20 KB target
- Signature or form photo cropped to just the relevant area.
- Scans done at 150 DPI, not 300 or 600.
- Long edge between 800 and 1000 px.
- Format JPG — the target-size box does nothing for PNG.
Leaving headroom under the ceiling
Portal checkers vary in how they measure. Some round up to the nearest KB, some compare against 1024-byte kilobytes instead of 1000-byte ones, and a few add a header length before comparing. Targeting 18–19 KB costs almost no visible quality and removes the entire class of borderline rejections.
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