AltFormr
File converter for macOS100% on deviceFree, including commercial use
Free file converter for Mac. Convert any format, no upload.
HEIC to JPG, MOV to MP4, WEBP to PNG, FLAC to MP3, Word to Markdown, and dozens more. Drag in your files, pick a format, and AltFormr handles the rest entirely on your Mac. Nothing is ever uploaded.
v1.8.1 · macOS 13+, including 27 Golden Gate · Apple Silicon & Intel · Signed & notarized by Apple · No account
01 How it works
Three steps, then you're done.
Drag in your files
Drop images, audio, or video onto the window: one file, a hundred, or a whole folder. Or press ⌘O to pick them, or ⌘V to paste from Finder.
Pick a format
AltFormr suggests the right target for each file. Change one, or set the format for every image, audio, or video file at once. Tune quality, size, or bitrate if you like.
Convert
Hit Convert and everything runs in parallel, right on your Mac. Converted files are new files, saved next to the originals or in a folder you choose, and AltFormr shows you how much space you saved.
Or skip all three steps
Just rename the file.
Turn on Convert on rename in Settings and AltFormr watches Finder for extension changes. Rename photo.heic to photo.jpg and AltFormr pops up to confirm, then converts the contents to match, right where the file sits. No drag, no menu.
02 Features
Everything macOS conversion should be.
A focused, native app that does one thing exceptionally well, without ever sending your files to the cloud.
Every common image
HEIC, JPG, PNG, WEBP, AVIF, TIFF, GIF and BMP: convert between any of them, or back into the same one to recompress. iPhone HEIC photos become shareable JPGs in a click, and you choose what goes behind transparency.
Video & audio too
MP4, MOV, MKV and WEBM for video; MP3, M4A, WAV, FLAC, AAC and OGG for audio. Pull the audio out of any video, or turn a clip into a GIF.
Documents ⇄ Markdown
Turn Word (.docx), RTF, ODT, HTML and plain text into clean Markdown, and Markdown right back into any of them. A whole new category, entirely on your Mac.
New in 1.2
PDFs, slides & sheets to Markdown
Pull the text out of a PDF, the slides out of a PowerPoint (.pptx) or the cells out of an Excel (.xlsx) file as tidy Markdown, then export Markdown back to a polished PDF.
New in 1.2
Images into one PDF
Drop a folder of scans or photos and combine them into a single PDF, one image per page, in the order the folder reads: page 2 after page 1, not after page 19. It's a long job on a big folder, so the button becomes Stop while it runs; stopping keeps no half-finished file and tells you how many pages it had ready.
Stop added in 1.4.0
Shrink big videos
Cap any video at 1080p, 720p or 480p to make it dramatically smaller for email or the web. Aspect ratio is kept, and a smaller clip is never blown up.
Fit any size limit
Need a clip under 10 MB for Discord or 25 MB for email? Pick a target (or type your own) and AltFormr two-pass encodes the video to land just under it, no guessing.
New in 1.1
Shrink it, keep the format
A JPG that has to stay a JPG, or an MP4 that has to stay an MP4, can still get smaller. Pick the format the file already is (marked "(recompress)") and every quality, resize and resolution setting applies to it.
New in 1.4.0
Size limits for photos too
Get a picture under 500 KB for an upload form, or resize to exactly 1920 px wide for the web. AltFormr gives up as little quality as it can to hit the number, and never enlarges a smaller image.
New in 1.4.0
100% on your Mac
Nothing is uploaded, ever. No account, no cloud, no usage analytics. Converting itself needs no connection at all; the only call AltFormr makes is its update check.
Strip location & EXIF
Flip one switch to remove GPS location, camera details and other EXIF metadata from your photos as they convert, so what you share doesn't reveal where it was taken.
Privacy
Hybrid engine
macOS's own ImageIO reads HEIC with full fidelity; a bundled FFmpeg handles everything else. Best-in-class quality, with nothing extra to install.
Batch a whole folder
Drop dozens of files (or a folder, subfolders and all) and convert them at once, in parallel, with live progress and a Stop button. Each file keeps its own target format and settings, each card says which folder it came from when the queue spans more than one, and the summary at the end counts the failures as well as the successes.
Learns your habits
AltFormr remembers the format you last chose for each file type, so the next HEIC defaults to PNG if that's what you always pick. Less clicking, every time.
Fine control
Quality sliders, resize by percentage or pixel width, video bitrate, audio sample rate and mono/stereo, and GIF frame-rate & width, set globally or per individual file from a tidy gear popover.
Signed & notarized
Opens with a normal double-click, no "unidentified developer" warning, no Open Anyway, no Terminal. Notarized by Apple.
No warnings
Built for everyone
Full keyboard control, VoiceOver labels throughout, automatic light & dark, and reduced-motion support. The whole UI meets WCAG 2.1 AA contrast.
WCAG 2.1 AA
Light & quick
A native app that launches instantly, follows your Mac's Auto Light/Dark appearance (or force one with a header button), and remembers the folders you convert from most. Also exports ICNS & ICO icons.
ICNS · ICO
Speaks your language
AltFormr's interface comes in 13 languages (German, English, Spanish, French, Italian, Japanese, Korean, Dutch, Polish, Brazilian Portuguese, Russian, Turkish and Simplified Chinese) and auto-detects your Mac's language on first launch. Switch anytime from the in-app flag picker; the whole window follows, sheets included.
Make ringtones
Turn any song or audio file into a trimmed, faded .m4r ringtone: pick the start time and length (up to 40s) per file, or convert a whole batch at once.
New in 1.3.10
Convert from Finder
Right-click any file or batch in Finder, pick Convert with AltFormr from Quick Actions, choose a format and the converted files land next to the originals. AltFormr's window never opens.
New in 1.6
Convert on rename
Enable it in Settings and AltFormr watches for file renames that change the extension. Rename
New in 1.6.5
photo.heic to photo.jpg and AltFormr asks before converting the contents to match.Audio album art thumbnails
An MP3 or M4A with embedded cover art displays the artwork as its thumbnail instead of a generic icon, so you can tell your files apart at a glance.
New in 1.6.5
Filter & Quick Look
Type ⌘F to filter a long queue by name, and press Space to Quick Look any file exactly as Finder does. Right-click any row for its full action menu.
New in 1.6
Quick presets
Pick Web, Email or Archive and the image, video and audio settings change together. Web makes small WEBP photos and 720p video, Email goes tiny (JPG at half size, 480p video under 25 MB), and Archive keeps PNG, FLAC and top video quality.
Presets
Wider format reach
Reads JPEG XL (.jxl) and SVG alongside camera RAW (CR2, NEF, ARW, DNG and more), PSD, JPEG 2000 and older WMA, WMV and FLV files. Also writes OPUS, AIFF, M4B audiobooks, M4V and AVI, and turns an animated GIF into MP4, WEBM or MOV.
Documents to PDF, PDF to images
Save Word, RTF, ODT, HTML or text as a PDF, or turn each page of a PDF into a PNG or JPG, scanned pages included. A single picture can become a PDF too.
Keeps your original dates
Converted files can carry the created and modified dates of the originals, so your photo library and Finder sorting stay in order. It's on by default; switch it to today's date whenever you like.
A real Mac menu bar
File and Help menus, plus Settings (⌘,) for appearance and language, Check for Updates and a keyboard shortcuts sheet (⌘/). Every menu item runs the same control you see in the window.
New in 1.6
Open With & Dock drop
Right-click files in Finder and choose Open With > AltFormr, or drop them on AltFormr's Dock icon. Folders work too, and a mixed selection is queued the way a dropped folder is.
New in 1.4.0
Tucks into the menu bar
Closing the window hides AltFormr to the menu bar instead of quitting. Click its icon to Show or Quit, or click the Dock icon to bring it back. It reopens at the size and place you left it.
New in 1.6.5
Undo, retry & notifications
Clear all has an Undo, a failed-file count jumps you to each problem with Retry ready, and a notification tells you how a batch went if you've switched to another app.
New in 1.5.0
Previews on every card
See a thumbnail of each photo, video frame or album cover, with its pixel size and length beside it, so you know what you're converting before you press Convert.
03 Converts between
HEIC
JPG
PNG
WEBP
AVIF
TIFF
GIF
BMP
ICNS
ICO
MP4
MOV
MKV
WEBM
MP3
M4A
WAV
FLAC
AAC
OGG
DOCX
RTF
ODT
MD
PDF→MD
PPTX→MD
XLSX→MD
05 Pricing
Free for everyone.
AltFormr for macOS
Free forever
Personal and commercial use included
- The full app, every feature
- No account, no nag screens
- Free updates forever
- Personal and commercial use, no license required
06 Download & install
Get set up in seconds.
Download the app and drag it into Applications. That's it. No Terminal, no Homebrew, no sign-up.
Version 1.8.1 · Released November 2, 2026 · Free updates forever
macOS 13 Ventura or later, including macOS 27 Golden Gate · Apple Silicon or Intel
Everything AltFormr needs (including the FFmpeg engine) is built right into the app. Nothing else to install.
Opens with a double-click
AltFormr is signed with an Apple Developer ID and notarized by Apple, so it opens cleanly the first time, no
Open Anyway trip through System Settings, no Terminal. Open the DMG, drag AltFormr into Applications, and launch it.Check the file you downloaded
AltFormr is signed with an Apple Developer ID and notarized by Apple, and macOS checks that every time you open it. That is the check that catches a file altered on its way to you. To confirm it yourself, compare the SHA-256 of your copy with the one published for the
AltFormr.dmg this page serves.SHA-256 checksum
Published checksum
Run this on your download and compare
shasum -a 256 ~/Downloads/AltFormr.dmg
Or have your Mac compare them for you: save AltFormr.dmg.sha256 beside the download and run shasum -a 256 -c AltFormr.dmg.sha256.
07 FAQ
Common questions.
Is AltFormr really free?
Personal use is free forever: all formats, no account, no trial timer, no watermarks. It is free for commercial use at work too, with no license to buy and no account.
Does AltFormr upload my files anywhere?
No, your files never leave your Mac. Every conversion runs locally, with no account, no cloud and no usage analytics. AltFormr makes one network connection: a check with twoplus11.com about once a week for a new version, which sends the app version and nothing else and can be switched off in the sidebar under Updates (installing an update then downloads it from us). Nothing about your files is involved.
What can it convert?
Images (HEIC, JPG, PNG, WEBP, AVIF, TIFF, GIF, BMP), icons (ICNS, ICO), audio (MP3, M4A, WAV, FLAC, AAC, OGG), video (MP4, MOV, MKV, WEBM), and documents. Word (.docx), RTF, ODT, HTML and plain text convert to and from Markdown, and it can pull a PDF, PowerPoint or Excel file into Markdown or export Markdown to PDF. It can also extract the audio track from a video, or turn a clip into an animated GIF.
Can it make a file smaller without changing the format?
Yes. Pick the format the file already is (it appears in the menu marked (recompress)) and AltFormr re-runs the encoder with your quality, resize and resolution settings. That's how you get a JPG that has to stay a JPG under a size limit, or a large MP4 down to 720p while it stays an MP4. For photos there's a Fit size budget in KB or MB, and a Resize menu that takes a maximum pixel width as well as a percentage; neither will ever enlarge something that's already smaller.
Does AltFormr change my original files?
A conversion always writes a new file. Your original is read, never rewritten. Where that new file lands is up to you: next to each original, or in a folder you pick. If a file of that name is already sitting there, Keep both (the default) gives the new one a distinct name; Replace overwrites what is there. Replace has one hard limit: it will never write over a file you put in the queue, so a source of yours cannot be destroyed by an output, not by a conversion, and not by page 2 of a PDF you are turning into images.
Why does it handle iPhone HEIC photos so well?
AltFormr uses macOS's own ImageIO (the same engine Photos and Preview use) to read HEIC, so your iPhone photos convert with full fidelity. A bundled FFmpeg handles every other format.
Can it remove the GPS location from my photos?
Yes. Turn on Remove photo metadata and AltFormr strips EXIF, GPS location and camera details from every image format it writes as it converts, all on your Mac. It's on automatically in the Web and Email presets, so anything you share is scrubbed of where and how it was taken.
Will macOS warn me about an unidentified developer?
No. AltFormr is signed with an Apple Developer ID and notarized by Apple, so it opens with a normal double-click the first time. No Open Anyway dance, no Terminal.
How do I update AltFormr?
AltFormr updates itself. It checks about once a week and, when a new version is out, shows you what changed and offers to install it. The download is signature-checked, and one that doesn't verify is refused. You can also check on demand from the Updates button, turn the automatic check off in the sidebar under Updates, or download the AltFormr.dmg from this page and drag it into Applications yourself. Your preferences carry over either way.
Is there a Windows version?
Yes, in beta. AltFormr for Windows runs on Windows 10 (version 1809 or later) and Windows 11, 64-bit, and installs without admin rights.
Does AltFormr have quick presets?
Yes. When your queue holds photos, video or audio, a Quick preset row appears in the sidebar with Web, Email and Archive. One click sets the image, video and audio options together: Web makes small WEBP photos, 720p video and M4A audio; Email makes JPG photos at half size, 480p video under 25 MB and lighter audio; Archive picks PNG, FLAC and the highest video quality and keeps photo metadata. You can still adjust any setting afterward.
Which less common formats does AltFormr support?
On the output side it also writes OPUS, AIFF and M4B audiobooks, plus M4V and AVI video. On the input side it reads camera RAW files (CR2, NEF, ARW, DNG and more), PSD, JPEG 2000 and older WMA, WMV and FLV files. An animated GIF can be converted to MP4, WEBM or MOV.
Can AltFormr make a PDF from a Word document, or turn a PDF into images?
Yes. Word, RTF, ODT, HTML and text files can be saved as PDF, and any picture can become a PDF on its own. Going the other way, a PDF can be turned into one PNG or JPG per page, and that works for scanned PDFs with no text layer. Everything runs on your Mac.
Do converted files keep the original dates?
By default, yes. Keep original dates gives each converted file the created and modified dates of the file it came from. If you would rather have the date of the conversion, switch the setting in the sidebar under Save to.
How do I send files to AltFormr from Finder or the Dock?
Select files or folders in Finder and choose Open With, then AltFormr, or drop them on AltFormr's Dock icon. They are queued the same way as a drag into the window, and AltFormr launches first if it isn't running. AltFormr never becomes the default app for your files, so double-clicking a photo still opens Preview.
What happens when I close the AltFormr window?
AltFormr hides to the menu bar instead of quitting, and tells you so the first time. Click its menu bar icon to Show or Quit AltFormr, or click the Dock icon to bring the window back. It reopens at the size and position you left it.
What if some files in a batch fail?
The queue header shows how many files failed. Click it to jump to the first one with its Retry button ready, and click again for the next. When a batch finishes while you are in another app, a notification says how many converted, how many failed and how much space you saved. Clear all has an Undo button, so a misclick doesn't cost you your queue.