File formats explained

The everyday photo format, understood by every device made in the last thirty years.

Photographs and anything you need to send to someone without thinking about whether they can open it. It throws away detail to save space, so avoid re-saving the same JPEG over and over.

Convert to PNG, WebP, AVIF, GIF, BMP, TIFF, ICO, TGA, WBMP, PDF

Lossless image format with transparency.

Screenshots, logos, diagrams and anything with sharp edges or text. Nothing is thrown away, so the file is larger than a JPEG but stays crisp however many times you re-save it.

Convert to JPEG, WebP, AVIF, GIF, BMP, TIFF, ICO, TGA, WBMP, PDF

Google’s web image format — roughly 30 percent smaller than JPEG at the same quality.

Images on a website you control. Every current browser reads it, but older desktop software and some print shops still do not.

Convert to JPEG, PNG, AVIF, GIF, BMP, TIFF, ICO, TGA, WBMP, PDF

The smallest of the modern web formats, built on the AV1 video codec.

Squeezing a photo-heavy page as small as it will go. Compresses better than WebP but takes noticeably longer to encode.

Convert to JPEG, PNG, WebP, GIF, BMP, TIFF, ICO, TGA, WBMP, PDF

What an iPhone saves photos as by default.

Nothing, once the photo leaves the phone — Windows and most websites cannot open it. Convert to JPEG or PNG and the problem disappears.

Convert to JPEG, PNG, WebP, AVIF, GIF, BMP, TIFF, ICO, TGA, WBMP, PDF

The old animated format, limited to 256 colours per frame.

Short looping animations that need to work absolutely everywhere, including in email. For anything longer than a few seconds, WebP or a video file will be a fraction of the size.

Convert to JPEG, PNG, WebP, AVIF, BMP, TIFF, ICO, TGA, WBMP, PDF

Windows’ uncompressed bitmap, unchanged since 1990.

Feeding old industrial or medical software that refuses anything else. Files are enormous — a photo can be twenty times the size of the same image as PNG.

Convert to JPEG, PNG, WebP, AVIF, GIF, TIFF, ICO, TGA, WBMP, PDF

The archival and print format — lossless, multi-page, and able to hold CMYK colour.

Sending artwork to a printer, scanning documents, and long-term storage where you cannot afford generation loss.

Convert to JPEG, PNG, WebP, AVIF, GIF, BMP, ICO, TGA, WBMP, PDF

Windows icon container, holding several sizes of the same image in one file.

A website favicon or a Windows program icon. We write the usual set of sizes from 16 to 256 pixels.

Convert to JPEG, PNG, WebP, AVIF, GIF, BMP, TIFF, TGA, WBMP, PDF

Truevision Targa — a simple format that game engines and 3D tools still use for textures.

Texture work and older rendering pipelines that expect uncompressed image data.

Convert to JPEG, PNG, WebP, AVIF, GIF, BMP, TIFF, ICO, WBMP, PDF

A one-bit black-and-white format from the era of WAP phones.

Embedded displays and e-paper panels that take nothing but pure black and white.

Convert to JPEG, PNG, WebP, AVIF, GIF, BMP, TIFF, ICO, TGA, PDF

A Photoshop document, with all its layers.

We read it and flatten it to a normal image, which is what you want when someone sends you a PSD and you do not own Photoshop.

Convert to JPEG, PNG, WebP, AVIF, GIF, BMP, TIFF, ICO, TGA, WBMP, PDF

A drawing described as shapes and coordinates rather than pixels, so it stays sharp at any size.

Logos, icons and diagrams. Converting to PNG or JPEG fixes it at one resolution, so pick the size you actually need.

Convert to JPEG, PNG, WebP, AVIF, GIF, BMP, TIFF, ICO, TGA, WBMP, PDF

The format that looks the same everywhere, because it carries its own fonts and layout.

Anything final: contracts, invoices, forms, things going to print. Not for documents you still need to edit.

Convert to DOCX, ODT, RTF, TXT, HTML, Markdown, PPTX, JPEG, PNG, TIFF

Microsoft Word’s current format.

Documents that other people still need to edit and comment on.

Convert to PDF, ODT, RTF, TXT, HTML, Markdown, PPTX

Word’s format from before 2007.

Opening old archives. Convert to DOCX or PDF — current Word warns about .doc and some versions refuse it outright.

Convert to PDF, DOCX, ODT, RTF, TXT, HTML, Markdown, PPTX

The open document standard, used by LibreOffice and OpenOffice.

Working without Microsoft Office, and for public bodies that require an open format.

Convert to PDF, DOCX, RTF, TXT, HTML, Markdown, PPTX

Rich Text Format — formatted text that almost every word processor ever written can open.

A safe middle ground when you do not know what software is on the other end.

Convert to PDF, DOCX, ODT, TXT, HTML, Markdown, PPTX

Plain text with no formatting at all.

Stripping a document down to its words — for a script, a database import, or to see what is actually there.

Convert to PDF, DOCX, ODT, RTF, HTML, Markdown, PPTX

A web page — text, layout and links, all as plain markup.

Publishing on the web, or turning a page you saved from a browser into a PDF you can file and send.

Convert to PDF, DOCX, ODT, RTF, TXT, Markdown, PPTX

Plain text with a light sprinkling of formatting marks.

Notes, documentation and anything headed for a static site generator.

Convert to PDF, DOCX, ODT, RTF, TXT, HTML, PPTX

A PowerPoint presentation — slides, notes, transitions and embedded media in one file.

Decks you still need to edit. Convert to PDF before sending, so nothing reflows on the other machine.

Convert to PDF, DOCX, ODT, RTF, TXT, HTML, Markdown

PowerPoint’s format from before 2007.

Opening old decks. Convert to PPTX or PDF to keep them usable.

Convert to PDF, DOCX, ODT, RTF, TXT, HTML, Markdown, PPTX

An Excel workbook — one file holding several sheets, with formulas and formatting intact.

Spreadsheets that other people still need to open, edit and recalculate.

Convert to CSV

Excel’s format from before 2007.

Opening old workbooks. Convert to XLSX to stop the compatibility warnings.

Convert to XLSX, CSV

A table as plain text, one row per line.

Moving data between programs. Nothing is kept except the values — no formulas, no colours, no second sheet.

Convert to XLSX

The open e-book standard, read by everything except a Kindle.

Reading on a phone, tablet or e-reader. Text reflows to the screen instead of being locked to a page size, which is why it beats PDF on small screens.

Convert to nothing yet — this format is on the list.

Amazon’s own e-book format, used by the Kindle and by nothing else.

Older Kindle devices. Anything sold in the last few years takes EPUB directly.

Convert to nothing yet — this format is on the list.

The format that made digital music portable, and the one every device on earth can play.

Anything that has to just work — car stereos, old phones, podcast feeds. Choose it when compatibility matters more than the last few percent of quality.

Convert to WAV, FLAC, OGG Vorbis, WMA, M4A (AAC), AAC, Opus, AIFF

Raw, uncompressed sound exactly as it was recorded — big files, nothing thrown away.

Editing, mastering and anything going into another program. A minute of CD-quality stereo is about 10 MB, so it is a working format, not a listening one.

Convert to MP3, FLAC, OGG Vorbis, WMA, M4A (AAC), AAC, Opus, AIFF

Lossless compression — about half the size of WAV with every sample still intact.

Archiving a music collection. Converting FLAC to WAV and back changes nothing at all; converting it to MP3 does, and there is no way back.

Convert to MP3, WAV, OGG Vorbis, WMA, M4A (AAC), AAC, Opus, AIFF

A free, patent-unencumbered alternative to MP3 that sounds better at the same size.

Games, open-source projects and anywhere licensing matters. Support on consumer hardware is patchier than MP3.

Convert to MP3, WAV, FLAC, WMA, M4A (AAC), AAC, Opus, AIFF

Microsoft's old audio format, common on Windows machines from the 2000s.

Mostly a format to convert away from. If you have a folder of WMA files from an old PC, MP3 or FLAC will play everywhere they do not.

Convert to MP3, WAV, FLAC, OGG Vorbis, M4A (AAC), AAC, Opus, AIFF

The format Apple devices record and sell music in — AAC audio in an MP4 container.

iPhones, iTunes and audiobooks. At the same size it sounds better than MP3, and almost everything modern plays it.

Convert to MP3, WAV, FLAC, OGG Vorbis, WMA, AAC, Opus, AIFF

The same codec as M4A, but as a bare stream instead of inside a container.

Broadcasting and streaming pipelines that expect a raw AAC stream. For listening on a device, M4A is the friendlier wrapper.

Convert to MP3, WAV, FLAC, OGG Vorbis, WMA, M4A (AAC), Opus, AIFF

The newest of the lot, and the best sound per kilobyte of anything here.

Voice, podcasts and web playback. At 64 kbps speech sounds better than MP3 at three times that. Older hardware will not play it.

Convert to MP3, WAV, FLAC, OGG Vorbis, WMA, M4A (AAC), AAC, AIFF

Apple's uncompressed format — the same idea as WAV, from the other side of the fence.

Logic, Pro Tools and older Mac audio work. If you are not in that world, WAV does the same job with wider support.

Convert to MP3, WAV, FLAC, OGG Vorbis, WMA, M4A (AAC), AAC, Opus

The archive format every operating system opens without extra software.

Sending a folder of files to someone. When in doubt, use this one.

Convert to 7Z, TAR, TAR.GZ

A newer archive format that packs considerably tighter than ZIP.

Large archives where the saving is worth it. The recipient may need to install 7-Zip first.

Convert to ZIP, TAR, TAR.GZ

A proprietary archive format from WinRAR.

We open RAR files, but nobody except WinRAR is allowed to create them — so we convert them to ZIP or 7Z instead.

Convert to ZIP, 7Z, TAR, TAR.GZ

A Unix container that bundles files together without compressing them.

Linux and server work, usually paired with gzip as .tar.gz.

Convert to ZIP, 7Z, TAR.GZ

A TAR bundle squeezed with gzip — the standard way to ship software on Linux.

Server backups, source code and anything you will unpack on a Unix machine.

Convert to ZIP, 7Z, TAR

2 hours on the free plan, 30 days on paid plans. You can delete a file yourself at any time.

No. Files go straight to encrypted storage, are converted in an isolated container, and are never used for training.

Yes, by default. You can turn it off in the settings.

Conversion runs on libvips, Ghostscript, qpdf and ffmpeg. Where quality is a trade-off, you set it.

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