File analyzer for WindowsStorage X-ray100% on device
Why is this file so big?
Drop any file (a PDF, photo, Office doc, video, Windows program, or a whole folder) and Heftr gives you an X-ray of exactly what's eating the bytes, a plain-English verdict, and a one-click smaller copy where it's safe. Entirely on your PC. Nothing is uploaded, and your original is never touched.
v1.1.7 beta · Windows 10 (1809+) & 11 · 64-bit · Installs without admin rights · No account
01 How it works
Drop it. See it. Shrink it.
Drop it in
Drag a file or a whole folder onto the window from File Explorer. Heftr recurses in and adds every item. Ctrl O to browse, Ctrl V to paste. Drop several at once to compare them.
See the breakdown
A segmented bar and a ranked list show exactly what's taking up the space, always reconciling to the real size on disk, so the segments add up to what File Explorer shows you.
Read the verdict
One plain-English sentence tells you why it's big ("62% of this folder is raw footage") so you know what's actually worth doing something about.
One-click smaller copy
Where there's a safe fix, Heftr shows the projected size first and writes a (smaller) copy next to your file. The original is never touched or deleted.
02 Features
Finally know what's eating the bytes.
One focused window that inspects a file or folder honestly, and only offers a fix when there's a safe one, without ever sending anything to the cloud.
The file-size X-ray
A genuinely beautiful segmented breakdown bar with a matching ranked list and live cross-highlighting. Every breakdown reconciles to the real size on disk, so the segments always add up to what File Explorer shows you.
Reconciles exactly
The biggest things inside
The breakdown says which kind of thing is eating the bytes. This says which one: a ZIP's members by their full path, a PDF's individual images with dimensions and codec, its embedded fonts by name, and whether each was subset to the characters used or carried whole. Every column sorts, from the keyboard.
Sortable columns
Shrink Office, ZIP & MSIX files
For docx, xlsx, pptx, zip, epub and Windows' own msix/appx packages, Heftr buckets every member by size, names the single biggest one, and re-encodes oversized PNG/JPEG media into a smaller copy. The file stays perfectly valid.
docx · xlsx · pptx · msix
PDF shrink that keeps text sharp
The most common "why is this PDF huge" case (embedded photos) is one click. Heftr downsamples the raster images via pypdf and Pillow while text and vectors stay vector, never rasterized. Duplicate identical streams are de-duplicated as a bonus.
Never rasterized
See inside a photo
For JPG, PNG, HEIC and TIFF, Heftr gives a byte-exact split of the actual pixel data vs an embedded preview vs the ICC color profile vs metadata, then re-encodes at a strength you pick and strips the preview and metadata into a smaller copy.
Byte-exact
Get it under X MB
Type a target and Heftr picks the gentlest fix intensity that still fits (for images, PDFs and Office/ZIP media) and shows the projected result before writing. Can't reach the target safely? It says so and saves the smallest it could. Press Stop and it writes nothing at all.
Target size
Folder mode: a mini-DaisyDisk
Drop a folder and get an interactive, fully accessible treemap of what's eating the space, biggest first, with a ranked list and the biggest individual files anywhere in the tree. Click any block to drill in. Junction and symlink loops are never followed, and paths past the old 260-character limit scan without choking.
Interactive treemap
Batch everything
Drop several files at once to rank and compare them, drill into any one, and shrink every item that has a safe fix in a single pass. Changed your mind ten files in? The button becomes Stop, and everything already finished is kept.
Stoppable
Video & audio, diagnosed
MP4, MOV, M4V, M4A, MP3 and WAV get a per-track Video vs Audio vs container breakdown and a bitrate verdict from pure-Python parsers, with no external tools needed for the mainstream formats. Drop an optional
No external tools
ffprobe.exe next to the app to extend coverage to AVI, WMV and MKV.Windows programs, X-rayed
Drop a
Windows only
.exe or .dll and see a real PE-section breakdown: code vs resources vs data vs the Authenticode signature vs any installer payload appended on the end. See exactly why that setup.exe is 300 MB. The Mac build has no equivalent for this.Hidden NTFS streams surfaced
Windows quietly attaches alternate data streams to files: most commonly
Windows only
Zone.Identifier, the "mark of the web" that records a file was downloaded. Heftr surfaces the bytes those streams use, which File Explorer's size column never counts.Never touches your original
Heftr is non-destructive by design. Every fix writes a new (smaller) or (compressed) copy alongside the original, and existing files are never overwritten.
Originals untouched
Self-updates in place
Heftr checks for a new version, downloads it, verifies its signature and version before running anything, installs over itself and reopens: the job Sparkle does on the Mac. The Mac build still asks you to re-download by hand; this one doesn't.
Windows only
100% on your PC
Nothing is uploaded, ever. No account, no cloud, no usage analytics. The only times Heftr touches the network are an optional business-license check and the update check, which sends the app version.
Privacy
Built for everyone
Fully keyboard-driven (Ctrl O to open, Ctrl V to paste, the treemap and drill-in included) with Narrator labels, live-region announcements, Windows High Contrast support, and measured WCAG 2.1 AA contrast in light and dark, checked by 304 automated tests plus an axe-core sweep across 19 UI states.
WCAG 2.1 AA
13 languages
English, Spanish, French, German, Italian, Portuguese (BR), Dutch, Polish, Russian, Turkish, Japanese, Simplified Chinese and Korean. Heftr follows your Windows display-language list automatically, and the breakdown labels and verdicts are translated too, not just the chrome.
Localized
03 What it reads
PDF
Photos: JPG · PNG · HEIC · TIFF
Word: .docx
Excel: .xlsx
PowerPoint: .pptx
ZIP & EPUB
MSIX & APPX packages
Video & audio: MP4 · MOV · M4A · MP3 · WAV
Windows programs: .exe · .dll
Folders
Anything else → .zip
04 Beta
You're testing the first Windows build.
Heftr has been on the Mac for a while (it's at 1.2.0 over there). This is the Windows port's first public build: full engine parity plus a few Windows-only extras, backed by 304 automated tests and an axe-core sweep across 19 UI states.
What would help most
Drag & drop, for real
From File Explorer, the desktop, a search-results list, a network drive. Single files, multi-select, whole folders.
Folders you actually use
Point it at a real project folder, your Downloads, anything you're curious about, and check the breakdown against what you know is really in there.
The install itself
This build isn't code-signed yet, so tell me honestly whether SmartScreen scared you off, whether the shortcut and taskbar icon look right, and whether uninstall leaves anything behind.
Anything that looks wrong
Clipped text, a scrollbar where there shouldn't be one, an odd translation, a dialog you couldn't reach with the keyboard.
06 Pricing
Free. For everyone.
Personal use is free forever: every file type, unlimited files, no key, no account, no watermarks. Free for commercial use at work too, no license required.
Personal
Free forever
For individuals and personal projects
- The full X-ray: every file type, verdict and fix
- Office/ZIP/MSIX, PDF, image and target-size shrinking
- Folder treemap, batch and copy-report
- 100% on-device, nothing uploaded
- No account, no nag screens
- Free updates forever
At work
Free commercial too
No license, no subscription
- Everything in Personal
- Use it commercially at work, free
- No license to buy, ever
- Free updates forever
- Supports solo indie development
Heftr is free for everyone, including commercial use at work. There is no license to buy and no subscription. The same key works on the Mac build.
07 Download & install
Get set up in about a minute.
Run the installer and Heftr lands in your own user folder: no admin password, no UAC prompt, nothing else to install.
Version 1.1.7 beta · Heftr-Setup.exe · about 16 MB · Free updates forever
Windows 10 (version 1809 or later) or Windows 11 · 64-bit
Everything Heftr needs is inside the installer: no Python, no runtime to chase down. It does use the Microsoft Edge WebView2 Runtime to draw its interface, which ships with Windows 11 and reaches almost every Windows 10 machine through Windows Update. On the rare PC without it, Heftr will say so on launch and Microsoft's free installer is a one-click fix.
No admin rights needed
Heftr installs per-user into
%LOCALAPPDATA%\Programs\Heftr, so there's no UAC prompt and no argument with your IT department. Uninstall from Settings → Apps → Installed apps like anything else.Windows will almost certainly warn you. Here's the honest story.
This beta build of Heftr is not code-signed yet (the Windows signing pipeline exists but hasn't been run against this build), so Microsoft SmartScreen will very likely show a blue "Windows protected your PC" box with an "Unknown publisher" line the moment you run the installer. That's expected for an unsigned build fresh off my machine, not a sign anything is actually wrong with the file.
- Click More info
- Click Run anyway
08 FAQ
Common questions.
Is Heftr really free?
Personal use is free forever: no account, no trial timer, no watermarks, and the full app. If you use Heftr at work, free for commercial use at work too, with no license to buy.
What does Heftr actually do?
Drop any file or folder and Heftr shows you a breakdown of exactly what's taking up the space (images, fonts, content, media, overhead), a plain-English verdict of why it's big, and a one-click smaller copy where there's a safe one. Every breakdown reconciles to the real on-disk size, so the segments always add up to what File Explorer shows you.
Will Heftr change my original file?
Never. Heftr is non-destructive by design: every fix writes a new (smaller) or (compressed) copy next to the original, and existing files are never overwritten. Your original is left exactly as it was.
How does the PDF shrink work? Will my text get blurry?
No. Heftr downsamples the embedded raster images (usually photos) using pypdf and Pillow, while the text and vector graphics stay vector: they are never rasterized, so the copy is smaller but still crisp and selectable. It shows the projected size from a real dry-run first, and refuses gracefully when a PDF can't be shrunk safely (text-only, already efficient, or password-protected).
What kinds of files can Heftr inspect and shrink?
Office and ZIP files (docx, xlsx, pptx, zip, epub), MSIX/APPX packages, PDFs, images (jpg, png, heic, tiff), video and audio, Windows programs (exe, dll), folders, and anything else. It has a working one-click fix for Office/ZIP/MSIX media, images, PDF images, and a compress-to-zip for generic files. Video is diagnosed and handed off to Squishr for the actual re-encode; folders get a read-only treemap.
Can Heftr compress video?
Heftr diagnoses video (per-track Video vs Audio vs container sizing and a bitrate verdict), but it hands the actual re-encode to Squishr, its sibling app built for that. Heftr never re-encodes video pixels itself.
How does the business license work?
Heftr is free for personal and commercial use. No license key needed. If you find it useful at work, you can support development from the tip jar at the bottom of the page.
Does Heftr upload my files anywhere?
No. Every analysis and every fix runs entirely on your PC. Nothing you open is ever uploaded, and there's no account and no usage analytics. The only times Heftr contacts our server are to validate a business license key or to check for updates, which sends the app version.
What is folder mode?
Drop a folder and Heftr draws an interactive, fully accessible treemap (a mini-DaisyDisk) of what's eating the space, biggest first, alongside a ranked list and the biggest individual files anywhere in the tree. Click any block to drill in. Junction and symlink loops are never followed, so they can't hang a scan or double-count, and paths past the old 260-character limit are handled via the
\\?\ prefix.Can I get a file under a specific size?
Yes. Target-size mode ("get it under X MB") picks the gentlest fix intensity that still fits for images, PDFs and Office/ZIP media, and tells you the projected result before writing anything. If the target can't be reached safely, it says so and saves the smallest copy it could manage.
Can I stop a shrink once it's started?
Yes. A batch shrink walks every file one full re-encode at a time, and a fit-to-target re-encodes once per quality step. Either can take minutes. The button becomes Stop, and Escape works too. A stopped batch keeps and counts everything it already finished; a stopped fit writes nothing at all, because a "smaller" copy from a quality step Heftr never finished choosing is not the file you asked for.
Why did Windows show a blue "protected your PC" warning?
Because this beta build isn't code-signed yet: the publisher shows as "Unknown publisher" rather than a verified name, and SmartScreen has no download history for a brand-new file. Click More info → Run anyway. See the install section for the full explanation, and please don't click through that box for software from anywhere else you don't trust.
How do I update Heftr?
It updates itself, and this is one place the Windows build is actually ahead of the Mac one. Heftr checks for a new version, downloads the installer, verifies its signature and version before running anything, installs over itself and reopens. If any check fails it deletes the download and sends you to the download page instead. The Mac build still asks you to re-download and drag it into Applications by hand. Your settings carry over.
How is this different from the Mac version?
Same X-ray, same verdicts, same safety rules. The engine was rebuilt on Windows APIs rather than macOS ones. A few things are genuinely different: this build reads Windows programs (.exe/.dll) with a real PE-section breakdown, surfaces hidden NTFS alternate-data-stream bytes like
Zone.Identifier, sizes everything base-1024 to match File Explorer, and updates itself in place, none of which the Mac build does. A business license key works on both.Where do my settings live, and what does uninstalling remove?
Preferences sit in
%APPDATA%\Heftr and your license key in your user profile. Uninstalling removes the app from %LOCALAPPDATA%\Programs\Heftr; delete those two if you want every trace gone. Nothing is written outside your user account, and nothing goes in the registry beyond the uninstall entry.