Compress an image to under 40 KB
40 KB, as the form asks — the clearest picture that still fits.
Drop files here
or click to choose from your deviceAccepted: JPG, JPEG, PNG, WEBP, AVIF, GIF, BMP, HEIC, HEIF
Up to 3 files per runUp to 20 MB per file5 runs per dayRemove limits with Pro✓ Works offline
Your files stay on your device
This tool runs entirely in your browser. Nothing is uploaded, nothing is stored, and you can even turn off your internet connection before you start.
Example
Example: two photos for a form that wants between 20 and 40 KB
The form accepts a photo of 20 to 40 KB. Two candidates: photo-a.jpg, 3024 × 4032 pixels from a phone and a few MB, and photo-b.jpg, an older 480 × 600 scan of 15 KB. Settings: Maximum dimension Original size, Output format Keep original format.
- The target is 40,000 bytes. photo-a.jpg is tried at quality 0.92, then 0.40, and made smaller in rounds while 0.40 is still too big; the last search keeps the highest quality that fits.
- photo-b.jpg is a JPG already under 40,000 bytes, so it is handed back untouched, still 15 KB: saving it again would only lose quality.
- 15 KB is under the form’s 20 KB minimum. On the increase image size page, at least 20 KB, it comes back at exactly 20,480 bytes, its pixels unchanged.
| File | Before | After Compress to 40 KB | For the 20–40 KB form |
|---|---|---|---|
| photo-a.jpg | 3024 × 4032, a few MB | just under 40,000 bytes | ready |
| photo-b.jpg | 480 × 600, 15 KB | unchanged, 15 KB | too small: increase it to 20,480 bytes |
Both photos inside 20–40 KB: one brought down, the other brought up. A form with a range checks both ends, and compressing never makes a small file bigger.
How it works
- Drop the photo or signature the form asks for — JPG, PNG or WebP.
- If the form also gives a width and height in pixels, resize first; otherwise just go ahead.
- Press Compress to 40 KB and check the size shown next to the file before you upload it.
Frequently asked questions
- What fits in 40 KB?
- Comfortably a passport-style photo with room to spare. A full-size phone photo is first saved at a lower quality and, if that is still too big, made smaller — to about 430 × 550 pixels for a photo at this target.
- Which forms ask for this size?
- Forms that allow a little more than the usual 20 KB, often "between 20 and 40 KB" or "under 40 KB", for a clearer face.
- How is 40 KB counted?
- The result stays under 40,000 bytes, so it passes whether the form counts a kilobyte as 1,000 or 1,024 bytes.
- The form says between 20 and 40 KB. Can the result be too small?
- From a big photo, no: the highest quality under 40,000 bytes is kept, which lands close to 40 KB. A JPG already under 40,000 bytes is returned untouched, though, so a 15 KB file stays 15 KB; bring it over 20 KB with the increase image size page.
- Should I resize first?
- If the form names pixels, yes: resize to them, then compress here. Otherwise leave Original size: the picture is made smaller only when quality alone cannot reach 40,000 bytes.
- Is my picture uploaded?
- No. Everything runs in your browser. The free plan handles 3 images per run, 20 MB each and 5 runs a day.