Free converters · Run in your browser
Free file converters
Short answer
165 converters for video, audio and images, all running in your browser with nothing uploaded. Some conversions only change the container and keep quality (11 of them copy the streams instead of re-encoding); others re-encode, which costs a little quality and can change the size a lot: a 29.82 MB PNG photograph became a 3.60 MB JPG, while a 94.6 KB text screenshot grew to 129 KB.
Images
Video
Audio and video to audio
Browse every pair
Key takeaways
- 49 video, 50 audio, 20 image and 46 video-to-audio converters, free and without upload or account.
- Copying is not converting: 11 video pairs are container swaps that copy the streams (MOV to MP4 is one), so quality and file size stay the same.
- Going to a lossless format does not repair anything: JPG to PNG made our 3.10 MB photo 29.97 MB with no quality gain.
- Going back costs space: WebP to JPG made our 2.33 MB photo 3.71 MB.
- HEIC from an iPhone is decoded in your browser by libheif compiled to WebAssembly.
Measured: what happens to the size
Image conversions were run through the converter's own steps in headless Chromium (the picture is drawn on a canvas and saved at quality 0.92, with a white background for JPEG). The files are public domain NASA scans, one with transparency, plus a screenshot of a page of this site.
| Conversion | Test file | Before | After | Change | SSIM |
|---|---|---|---|---|---|
| PNG to JPG | aldrin | 29.82 MB | 3.60 MB | -88% | 0.991 |
| PNG to JPG | screenshot | 94.6 KB | 129 KB | 37% | 0.992 |
| PNG to JPG | apollo11 | 18.86 MB | 3.84 MB | -80% | 0.958 |
| JPG to PNG | aldrin | 3.10 MB | 29.97 MB | +866% | 1.000 |
| WebP to JPG | aldrin | 2.33 MB | 3.71 MB | +59% | 0.981 |
| HEIC to JPG (92%) | aldrin, HEIC quality 75 | 4.35 MB | 3.58 MB | -18% | 0.989 |
The rows show why "convert" does not mean "smaller": the direction and the content decide. Photographs shrink going to JPG, flat graphics and text may not, and going to PNG always grows a lossy file.
Formats at a glance
| Format | Full name | Compression | Best for |
|---|---|---|---|
| MP4 | MPEG-4 Part 14 | Depends on the codec inside | Uploading anywhere: the format social platforms document first |
| MOV | QuickTime File Format (Apple) | Depends on the codec inside | iPhone recordings and Final Cut Pro projects |
| WebM | WebM (open web format) | Lossy | Video on web pages; YouTube accepts it, most short-form apps do not |
| MKV | Matroska | Depends on the codec inside | Archiving and playback in desktop players; most social platforms do not list it |
| GIF | Graphics Interchange Format | Lossless, but limited to 256 colors | Short silent loops in chats and documents; large files for their quality |
| MP3 | MPEG-1 Audio Layer III | Lossy | Music and podcasts that must play on every device |
| WAV | Waveform Audio File Format | Uncompressed | Editing and mastering, where every sample matters; very large files |
| M4A | MPEG-4 audio | Lossy or lossless | Apple devices and voice memos |
| FLAC | Free Lossless Audio Codec | Lossless | Archiving music at full quality in less space than WAV |
| JPG | JPEG image (.jpg) | Lossy | Photos; the image format every platform documents |
| PNG | Portable Network Graphics | Lossless | Screenshots, logos and graphics with text |
| WebP | WebP (Google) | Lossy or lossless | Smaller images on websites; social platforms mostly document JPEG and PNG instead |
| HEIC | High Efficiency Image Container (HEIF with HEVC) | Lossy | iPhone and iPad photos: Apple says it compresses better than JPEG at the same visual quality |
| SVG | Scalable Vector Graphics | Vector (no pixels) | Logos and icons that must stay sharp at any size |
The formats the converters read and write, with what each is for.
Copy or re-encode?
A video file has a container (MP4, MOV, MKV) around the picture and sound streams. When the target container can hold the same streams, the converter copies them: 11 of the video pairs work this way, so they are fast and lose nothing. When it cannot, the streams are decoded and encoded again, which is slower and loses a little quality. Each converter page says which of the two it does.
| Kind | Pairs | Container swaps (copy) | Re-encode |
|---|---|---|---|
| Video | 49 | 9 | 40 |
| Audio | 50 | 2 | 48 |
| Image | 20 | 0 | 20 |
| Video to audio | 46 | 0 | 46 |
Limits to know about
- Video and audio files up to 100 MB; the first conversion downloads a converter engine of about 30 MB once per visit.
- HEIC files are decoded up to 16,384 pixels on a side. The converted file does not carry the original's metadata, such as the date or location.
- Images are saved by the browser's own encoder, so sizes can differ a little between browsers.
Questions people ask
Are the converters free?
Yes, with no account and no watermark.
Are my files uploaded?
No. Every conversion runs in your browser.
Does converting reduce quality?
Container swaps do not. Re-encoding does a little, and a conversion to a lossless format such as PNG or WAV adds no loss but cannot restore detail that was already lost.
Why did my converted file get bigger?
Lossless targets are bigger by design (JPG to PNG was 9.7 times bigger), and WebP to JPG grew too. Flat graphics and text screenshots can also grow when converted to JPG.
Can I convert iPhone HEIC photos?
Yes. HEIC to JPG, PNG and WebP are supported, several files at once.
Is there a size limit?
Video and audio files up to 100 MB. Image size is limited by your device's memory.
Sources and how we checked
- MDN: Image file type and format guide (read 2026-10-09)
- FFmpeg Documentation: ffmpeg (read 2026-10-09)
- Apple Support: Using HEIF or HEVC media on Apple devices (read 2026-10-09)
Reviewed October 9, 2026. Every figure on this page comes from the measurements behind the linked tool pages, which are saved in data/seo/hub/evidence/2026-10-09.