PNG to JPG Converter
Save a PNG as a JPEG at the quality you choose, and see how many bytes that costs or saves.
Results
What this tool does
A PNG of a photograph is usually several times larger than it needs to be, because PNG records every pixel exactly and a photograph has no exact pixels worth keeping. Converting to JPEG trades a little detail for a much smaller file. Choose an image, set the quality, and the converted copy appears with the size comparison beside it. Transparent areas are filled with white, because JPEG cannot hold them.
Formula
difference = (size before − size after) ÷ size before
Variables
| Symbol | Meaning | Unit |
|---|---|---|
quality | Quality | % |
bytes_in | Original size, in bytes | — |
bytes_out | New size, in bytes | — |
OUT | New file size | — |
BF | It was | — |
SV | Difference | — |
PC | Saved | % |
DR | Smaller or bigger | — |
Worked example
- Quality88 %
- Original size, in bytes1,620,000
- New size, in bytes310,000
- New file size302.7 kB
- It was1.54 MB
- Difference1.25 MB
- Saved80.9 %
- Smaller or biggerSmaller
Limitations
- The calculation runs entirely in your browser. The values you type are never sent to a server.
Frequently asked questions
What happens to the transparent parts?
They become white. JPEG has no way to record transparency at all, so something has to be put behind the picture before it is saved, and white is the least surprising choice. If the transparency matters — a logo that has to sit on a coloured background — JPEG is the wrong format and PNG or WebP is the one to keep.