Image Converter
Turn a picture into PNG, JPEG or WebP in your browser, and see what the change does to the file size.
Results
What this tool does
Formats exist for different jobs, and files often arrive in the wrong one — a screenshot saved as a photograph, a logo saved in a format with no transparency, a modern file an old program refuses to open. Choose an image and a target format, and the converted file appears with a download button. The size comparison underneath shows whether the change cost you bytes or saved them.
Formula
difference = (size before − size after) ÷ size before
Variables
| Symbol | Meaning | Unit |
|---|---|---|
format | Save as | — |
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
- Save asimage/png
- Quality90 %
- Original size, in bytes1,200,000
- New size, in bytes640,000
- New file size625.0 kB
- It was1.14 MB
- Difference546.9 kB
- Saved46.7 %
- Smaller or biggerSmaller
Limitations
- The calculation runs entirely in your browser. The values you type are never sent to a server.
Frequently asked questions
Which format should I pick?
PNG keeps every pixel exactly and supports transparency, which makes it right for logos, screenshots and drawings, and wasteful for photographs. JPEG throws detail away to get small, which makes it right for photographs and poor for text and sharp edges. WebP does both jobs and produces smaller files than either, but very old software may not open it.