Reference
Every Format Smol Converts on a Mac
Smol converts images, PDFs, documents, spreadsheets, presentations, video, audio, tables and fonts on macOS, entirely on your own machine. The tables below list exactly what it can write, transcribed from the app’s own capability response rather than from marketing copy.
One distinction matters before you read them: Smol reads considerably more than it writes. The lists here are output formats. A file type missing from them may still be a perfectly good input.
What formats can Smol write?
| Category | Writes |
|---|---|
| Images | jpg · png · webp · avif · heic · tiff · bmp · gif · pdf |
| PDF to image | png · jpg |
| Documents | pdf · docx · odt · rtf · txt · html |
| Spreadsheets | pdf · xlsx · ods · csv · html |
| Presentations | pdf · pptx · odp |
| Video | mp4 · mov · webm · mkv |
| Audio (convert) | m4a · mp3 · wav · flac · ogg |
| Audio (compress) | aac · m4a · mp3 · wav · flac · ogg · opus |
| Tables / data | csv · tsv · json · ndjson · html · md · xlsx · numbers |
| Fonts | ttf · otf · woff · woff2 |
Note the audio split. aac and opus appear as compression targets but not as conversion targets, which is a real distinction inside the app rather than a documentation quirk.
Why does it read more than it writes?
Reading a format needs a decoder; writing one needs an encoder, and often a licence. Smol reads camera RAW files (CR2, NEF, ARW, DNG) and AVI video, but writes neither. The practical effect is that a RAW file or an AVI is a valid starting point, and the output lands in one of the formats above.
Two formats are worth naming because people look for them: AVI cannot be written(mp4, mov, webm and mkv can), and Apple’s .pages format cannot be written either.
What can you actually control?
- Images. Quality 0–100, maximum dimensions up to 32,768 px, and four resize modes (fit, fill, width, height).
- Video. CRF 0–63 and nine encoder presets from
ultrafasttoveryslow. - Audio. Bitrate 16–512 kbps, sample rate 8–192 kHz.
- Neural image compression. Writes avif, webp, jpg or png, and accepts a target size between 4 KB and 4 MB — a genuine “hit this file size” control rather than a quality slider.
- Upscaling. 2×, 3× or 4×, writing png, jpg or webp.
PDF compression works differently from the rest. Its five presets are long-edge pixel caps — roughly 600, 900, 1,200, 1,800 and 2,400 px — not fixed DPI targets, so the effective resolution depends on how large the image sits on the page. The presets are explained in full here.
What can Smol not do?
Stated plainly, because finding these out mid-job is worse than reading them here.
- PDF to image converts the first page only. A fifteen-page PDF produces one image. For every page of one document, Automator’s Render PDF Pages as Images is the right tool, and it is free. Covered here.
- Animated GIFs are not supported. Single-frame GIFs convert; animated ones fail. Use ffmpeg — walkthrough here.
- PDF compression presets do not strip metadata. That is a separate operation, and the PDF metadata story has a serious caveat worth reading.
- No CMYK conversion and no PDF/X output, which rules it out for professional print preparation.
When Smol is not the answer
For a single file, macOS already has what you need. sips is installed on every Mac and converts most image formats from one line. Preview exports images and PDFs without any install at all. Neither costs anything.
For the widest possible format matrix, a cloud converter wins outright — CloudConvert handles 212 formats to our 39, and does not need a Mac. That comparison is here. For scripted pipelines on a build server, ffmpeg and ImageMagick are the correct tools and always will be.
Smol earns its place when the work is repetitive, mixed-format, or needs to stay on your machine — a folder of 400 files in six formats, with one consistent output setting, and nothing uploaded.
Frequently asked questions
Does Smol convert RAW camera files?
It reads them. CR2, NEF, ARW and DNG are valid inputs, and the output lands in one of the supported image formats such as JPEG, AVIF or WebP. Smol does not develop RAW files, so exposure, colour and lens correction still belong in Lightroom or Capture One.
Can Smol convert a video to AVI?
No. Smol reads AVI but writes only mp4, mov, webm and mkv. If you specifically need an AVI output, ffmpeg will do it in one command. For almost every modern use, mp4 is the better target anyway.
Why is AAC listed under compression but not conversion?
They are separate operations inside the app. Compression targets include aac and opus; conversion targets are m4a, mp3, wav, flac and ogg. If you want an AAC file, run it as a compression job rather than a conversion.
How many pages does PDF to image convert?
One. A multi-page PDF produces a single image of the first page. For every page of one document, use Automator’s Render PDF Pages as Images action, which is free and built into macOS. Smol’s advantage is batching across many separate PDFs rather than splitting one.
Does converting a file upload it anywhere?
No. Every operation runs locally on your Mac using encoders bundled inside the app. There is no upload step and no account, which is why it works with the network switched off.
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