Free converter · Lossless transform
Convert JPG to PNG
Short answer
Drop your JPG file into the converter below and download the PNG file. It runs in your browser with the Canvas API; nothing is uploaded. The pixels are saved as a lossless PNG; transparency is kept, without further loss. Detail the JPG compression already removed does not come back, and the file is usually larger.
JPG to PNG; PNG is lossless but cannot restore JPG discarded detail. · Lossless transform · Browser-side via Canvas - nothing uploaded.
Key takeaways
- PNG stores the decoded pixels exactly: SSIM against the browser's decode of the JPG was 1.000, so the conversion adds no loss.
- It costs a lot of space: our PNGs were 7.9 to 12.1 times the size of the JPG (3.10 MB became 29.97 MB).
- PNG cannot bring back detail the JPG already discarded. The picture looks the same, only larger.
- Do not go round the loop: converting the PNG back to JPG at 0.92 gave 3.57 MB, +15.1% against the JPG you started with, and SSIM 0.990 against it.
Measured: JPG to PNG
Measured in headless Chromium with the converter's own steps: the image is drawn on a canvas, JPEG gets a white background, and the browser saves it at quality 0.92. SSIM compares the result with the browser's own decode of the input, flattened on white (1.0 would be identical). Test files: three public domain NASA scans (a 3840 × 3877 photo, a 2122 × 2644 portrait, a 3827 × 1588 handwritten document), the NASA Apollo 11 insignia as a 5380 × 5432 PNG with transparency, and a 1440 × 1000 screenshot of a page of this site. The PNG files for the photos were made losslessly from the JPEGs; the WebP files were made with libwebp at quality 85. Other browsers use their own encoders, so sizes can differ.
| Test file | Pixels | JPG | PNG | PNG against JPG | SSIM of PNG | JPG again | SSIM of JPG again |
|---|---|---|---|---|---|---|---|
| Photo (JPG) | 3840 × 3877 | 3.10 MB | 29.97 MB | 9.7 times | 1.000 | 3.57 MB | 0.990 |
| Portrait (JPG) | 2122 × 2644 | 733 KB | 8.88 MB | 12.1 times | 1.000 | 841 KB | 0.987 |
| Document scan (JPG) | 3827 × 1588 | 1.36 MB | 10.69 MB | 7.9 times | 1.000 | 1.28 MB | 0.984 |
Size of the PNG against the JPG, and what a trip back to JPG at 0.92 does.
The PNG is a perfect copy of what the browser decoded. The extra column shows why you should keep the original JPG: saving it to JPG again is another lossy step.
JPG vs PNG
| JPG | PNG | |
|---|---|---|
| Full name | JPEG image (.jpg) | Portable Network Graphics |
| What is inside | Lossy compressed pixels | Pixels compressed without loss |
| Compression | Lossy | Lossless |
| Transparency | No transparency | Transparency supported |
| Best for | Photos; the image format every platform documents | Screenshots, logos and graphics with text |
What you get
A lossless PNG; transparency is kept. JPG to PNG; PNG is lossless but cannot restore JPG discarded detail.
When JPG to PNG makes sense
- A program or form accepts PNG but not JPG.
- You will edit the picture several times: PNG does not lose more with each save, JPG does.
- You need a layer-ready file to add transparency in an editor.
Free tools:PNG to JPGCompress an imageJPG to WebP
Why the PNG is that big
A raw 24-bit color picture needs 24 bits for every pixel. JPEG gets a photograph down to a couple of bits per pixel by discarding detail the eye notices least. PNG keeps every pixel and can only compress what repeats.
| Test file | JPG | PNG | Raw 24-bit |
|---|---|---|---|
| Photo (JPG) | 1.7 bits | 16.1 bits | 24.0 bits |
| Portrait (JPG) | 1.0 bits | 12.7 bits | 24.0 bits |
| Document scan (JPG) | 1.8 bits | 14.1 bits | 24.0 bits |
This is why PNG suits flat graphics, where long runs repeat, and photographs belong in JPG.
When it does not
If you only need a smaller file, PNG is the wrong direction: the 3.10 MB photo became 29.97 MB. Keep the JPG, or compress it. MDN's image guide says JPEG is a good choice for lossy compression of still images and PNG is preferred for more precise reproduction of source images; converting a JPG does not give the PNG a more precise source.
Questions people ask
Is this JPG to PNG converter free and private?
Yes. It is free, needs no account and runs entirely in your browser, so the file never leaves your device.
Will converting JPG to PNG reduce quality?
No further loss: PNG stores the decoded pixels exactly.
Does JPG to PNG improve quality?
No. PNG keeps the pixels exactly as the JPG decodes, but it cannot restore detail the JPG removed.
Why is the PNG so much bigger?
PNG is lossless and describes every pixel; JPG discards detail. Ours were 7.9 to 12.1 times bigger.
Will I get a transparent background?
No. A JPG has none, so the PNG has none either. Remove the background in an editor.
Is my image uploaded?
No. The conversion runs in your browser.
Can I convert PNG back to JPG without damage?
Not without a further loss: at 0.92 our round trip scored SSIM 0.984 to 0.990 against the original JPG.
What is the difference between JPG and PNG?
JPG is lossy and small, made for photographs. PNG is lossless, supports transparency and suits screenshots and graphics.
More converters
Sources and how we checked
- MDN: Media container formats
- MDN: Web audio codec guide
- MDN: Image file type and format guide
- FFmpeg documentation: stream copy
- MDN: Image file type and format guide (read 2026-10-09)
- Wikimedia Commons: Buzz salutes the U.S. Flag (NASA, public domain), one of the photographs used (read 2026-10-09)
Reviewed October 8, 2026. What the converter writes was measured with ffprobe on the same FFmpeg build your browser downloads; format descriptions follow MDN's media guides.