Images
Everything Windows has a codec for, including HEIC and AVIF. Animated GIFs play, and zooming in re-decodes at full resolution. PNG · JPG · JPEG · JFIF · JPE · GIF · BMP · DIB · TIF · TIFF · ICO · WEBP · HEIC · HEIF · AVIF · JXR · WDP
Press Space. See the file.
Quick Preview brings macOS Quick Look to Windows. Select anything in File Explorer, tap Spacebar, and it appears: images, documents, code, archives, audio, video. Tap Space again and it is gone.
- Completely free
- No account
- No telemetry
- 8.3 MB
Windows 10 1809+ or Windows 11, x64 · free forever, no trial, no paid tier
Illustration: a File Explorer window of photos. One file is selected, Space is pressed, and a preview window opens over Explorer showing the image with its type, size and dimensions.
How it works
One key. That's the whole thing.
Quick Preview sits in the tray and waits for a single key. It never opens the file's application, and it never writes to the file.
Select a file, press Space, and it appears. Press it again and it closes, handing focus straight back to Explorer exactly where you left it. There is no second shortcut to learn, and nothing to configure.
It knows where you are
Anywhere in File Explorer, or on the desktop. Multiple selections and network paths work too.
It stays out of the way
Space is only taken while Explorer or the desktop is in front, never in your editor, your browser, or a game.
It follows along
Click another file and the preview changes with it, without touching the keyboard again.
Formats
It previews what you actually have
And when it meets something it does not know, it shows a metadata card, never a blank window.
Documents
PDF page by page, and Office files laid out from their real geometry: theme colours, tables and shapes, with no Office installed. PDF · DOCX · DOCM · DOTX · XLSX · XLSM · XLTX · PPTX · PPTM · POTX
Text and code
Syntax highlighting, line numbers and encoding detection. A 2 MB log opens as fast as a 2 KB one. TXT · LOG · MD · MARKDOWN · JSON · XML · YAML · YML · CSV · TSV · INI · CFG · CONF · TOML · CSS · SCSS · LESS · HTML · HTM · SVG · JS · MJS · CJS · TS · JSX · TSX · C · H · CPP · CC · HPP · CS · JAVA · KT · GO · RS · PY · RB · PHP · SWIFT · SQL · SH · BASH · ZSH · PS1 · PSM1 · BAT · CMD · GITIGNORE · EDITORCONFIG · ENV · CSPROJ · PROPS · TARGETS · SLN · MANIFEST · CONFIG · LOCK · DIFF · PATCH
Archives
The contents are listed straight out of the index. Nothing is ever extracted to disk to show you what is inside. ZIP · TAR · GZ · TGZ · 7Z · RAR · BZ2 · TBZ · XZ · LZH · CAB · JAR · WAR · NUPKG · VSIX · EPUB · XPI · WHL · CRX · APPX
Audio and video
Playback, album art, and the metadata Windows already knows: length, bitrate, dimensions, artist. MP3 · WAV · FLAC · M4A · AAC · OGG · OGA · OPUS · WMA · AIFF · AIF · MID · MIDI · MP4 · M4V · MOV · MKV · AVI · WEBM · WMV · FLV · MPG · MPEG · 3GP · TS · MTS
Folders
A bounded top-level listing with real shell icons. Enter steps inside, Backspace comes back out. Shell icon · Name · Type · Size · Date modified · Item count · Folder or file
Everything else
An unknown extension still gets a card: name, type, size, dates and whatever else the shell can tell it. Name · Extension · Type description · Size on disk · Created · Modified · Attributes · Shell icon at full resolution
Privacy
Your files never leave your computer
Not a policy, a description of what the code does. Every line below is a default you can check in Settings, or read in the source.
Nothing is uploaded, ever
No telemetry, no analytics, no crash reporting, no account. The only part of the app that can open a network connection is the update checker, and out of the box it has no address to call, because the update source is empty and automatic checks are off until you turn them on yourself.
Read-only, always
Files are opened for reading and never for writing, so it cannot modify or move one. It does not lock them either, so you can keep editing a file while you preview it.
Nothing inside a file is run
No macros, no scripts. Office files are read as ZIP and XML rather than through Office, and HTML or SVG renders with scripting disabled and no network access of its own.
Archives are listed, not extracted
Entries are read from the index and nothing is written to disk. Their paths are validated too, so a crafted archive cannot point at somewhere outside itself.
Logs hold extensions, not contents
Diagnostics record what kind of file and how large, never what was in it, and never its name or path unless you switch that on yourself for troubleshooting.
It all lives in one folder
Settings and logs sit in %LOCALAPPDATA%\QuickPreview and nowhere else. Uninstalling is a
per-user removal that takes them with it.
Details
The parts you only notice when they are missing
Follows your selection
Click a different file in Explorer and the preview changes with it. No second keypress, and Explorer keeps focus.
Arrow through a folder
Left and right walk the files beside it, and Explorer's own selection moves to match, so closing leaves you where you ended up.
Reloads as the file changes
Edit and save a file while previewing it and the preview catches up on its own. Delete it and it says so rather than showing something stale.
Images decode out of process
Image codecs are native, and a crash in one cannot be caught. So decoding happens in a separate process; if it dies, the app does not.
Follows your theme
Light, dark or whatever Windows is doing, with a real acrylic backdrop on Windows 11 and high-contrast support throughout.
Costs nothing while idle
Measured on a Windows 11 laptop: 0.035% of one core, 14 MB of private memory, and just over half a second from launch to ready.
Zoom without waiting
Images open fitted to the window and re-decode sharper only when you zoom past what is on screen. A 200 MP photo costs what you can see.
Refuses politely
A malformed file, a decompression bomb or an executable gets a clear card explaining why, not a hang and not a crash.
Keyboard
Every key it answers
Space
Open the preview; press again to close
Esc
Close
← →
Previous and next file; Explorer's selection follows
↑ ↓
Scroll the document, or move through a folder listing
Ctrl + wheel
Zoom an image
Enter
Open in the default app, never for executables or scripts
Backspace
Step back out of a folder you opened inside the preview
FAQ
Worth knowing before you install anything
Is it really free?
Yes. No account, no trial period, no paid tier, no ads, and no feature held back for a version that costs money. If it saves you time you are welcome to buy me a coffee, and the app is identical whether you do or not.
Does it send anything over the internet?
No. There is no telemetry and no analytics. The only component that can make a network request is the update checker, and by default no update source is configured and automatic checks are switched off, so a fresh install never opens a connection at all.
Will it steal Space from my other programs?
No. The key hook has to be global, because Windows offers no per-application one, but the handling is scoped. On every Space it checks which window is in front and only acts for File Explorer, the desktop, or its own preview window. It also confirms the focused control is a file list rather than a text box, which is why Explorer's rename box and search box still get their spaces. Everything else, from your editor to your browser to a game, is passed straight through, typically in microseconds.
Do I need Microsoft Office or a PDF reader installed?
No. DOCX, XLSX and PPTX are read directly as the ZIP-and-XML packages they actually are, so Office never has to be present or launched. PDF rendering uses the engine already inside Windows.
Why does Windows warn me when I install it?
Because the installer is not code-signed. SmartScreen warns about any unsigned installer regardless of what is in it: choose More info, then Run anyway. A certificate is an annual fee charged for the privilege of not being warned about, and this app is free, so it does not have one.
What a certificate is genuinely useful for is stopping someone who takes over the download server from handing you a different build later. That part is solved a different way, and for nothing: each release manifest is signed with a key held only by the author, and Quick Preview refuses any update the key did not sign. Verify the first download yourself, and every one after it is checked for you.
Does it replace or modify File Explorer?
No. It is an ordinary application that runs beside Explorer and installs nothing into it: no shell extension, no add-in, no preview-pane handler. That was deliberate: in-process Explorer code can take Explorer down with it and makes uninstalling messy. Explorer's own preview pane is untouched and keeps working.
What does it cost while it is just sitting there?
Measured on a Windows 11 x64 laptop: 0.035% of one core at idle, 14.1 MB of private memory, and 536 ms from launch to the point where Space works. A 4000 × 3000 image previews in about 20 ms cold, and effectively instantly from cache.
How do I uninstall it?
Settings → Apps → Installed apps, like anything else. It is a per-user install that never needed
administrator rights, so removing it does not ask for them either, and it takes its startup entry and
its %LOCALAPPDATA%\QuickPreview folder with it.
Does it run on ARM64?
Honestly: unknown. Nothing in the code is x64-specific and no native library is bundled. The PDF and image work goes through Windows itself, which is part of why it was built that way. But no ARM64 package has been built or tested, so it is not claimed.
Where do my settings live, and can I read them?
In %LOCALAPPDATA%\QuickPreview\settings.json, plain JSON you can open, read and edit by
hand. Anything out of a sensible range is clamped on load rather than trusted, and the logs sit beside
it in the same folder.
Download
Judge it yourself
There are no star ratings on this page, no testimonials and no review count. One student wrote this in the evenings, and none of that would mean much yet anyway. What is true instead: it costs nothing, it installs in seconds without administrator rights, and it uninstalls just as fast. Point it at one folder of your own files and press Space once.
The portable build carries the whole .NET runtime twice, once for the app and once for its image-decoding worker, which is why it is so much larger than the installer.
Windows 10 1809 or later, or Windows 11 · x64 · needs the .NET 8 Desktop Runtime (the portable build carries its own).
The installer is not code-signed. Windows SmartScreen will warn you on first run; choose More info then Run anyway. A certificate is a yearly bill, and this is free software, so there is not going to be one.
Updates are signed anyway. Every release manifest carries a signature from a key that exists only on the author's machine, and the app refuses any update that key did not sign. So the thing a certificate would actually protect, nobody slipping you a different build later, is covered without one.
ARM64 is untested. Nothing in the app is x64-specific and no native dependency is bundled, but no ARM64 package has been built or run.
Quick Preview is written by one student, in the evenings, and is free either way. If it saves you time, buy me a coffee.