Runs entirely in your browser
Point Strata at a folder or a whole drive. It maps everything inside, ranks the biggest files, finds duplicate copies by content rather than by name, and totals up the folders you can rebuild from scratch. Works on macOS, Windows and Linux, with nothing to install — and your files never leave your device.
Pick your home folder to find the big things, or a whole drive if your browser can reach it.
…or drag a folder here
Nothing is uploaded and nothing about your disk is saved in your browser. Close the tab and Strata forgets everything it read.
Reasonable. Download Strata as a single file and run it from your own disk instead. It is the whole app — one HTML file, no installer, no dependencies, nothing to unpack. Open it by double-clicking, with your Wi-Fi off if you like, and it behaves exactly as it does here.
The copy you download has the page counter removed, so it makes no network requests at all. It is captured before anything is scanned, so it can never contain your file names.
A browser can only ever see the folders you hand it. The Windows build reads a whole drive — including the places a web page is not allowed near — scans far faster, and can actually clean up, because a real application can put things in the Recycle Bin where you can get them back.
One file, about 133 MB. Nothing to install and no .NET runtime needed. It is not code-signed yet, so Windows SmartScreen will warn the first time — choose More info then Run anyway, or check the SHA-256 published with the release first.
Point it at C: and it maps the lot, in parallel, reporting anything Windows refused instead of quietly leaving it out of the total.
Everything it removes goes to the Recycle Bin. It refuses drives that have no Recycle Bin, because there a delete would be permanent.
Windows, System32, Program Files, ProgramData, the root of a drive, your profile folder and links are all off limits, whatever their size.
A link pointing back up its own tree would loop forever and double-count. Strata reports links rather than walking through them.
No update check, no licence server, no telemetry, no account, and no .NET to install. Measured while scanning: no connections and not one networking library loaded. Only Windows itself reaches out, to check an unsigned download the first time you run it.
macOS and Linux: not yet. The scanning engine is platform-neutral .NET and a build for them is real work rather than a rewrite, but I will not put up a download I cannot build, sign and test myself. Until then the version on this page runs there today.
Blocks are coloured by the kind of file filling them, so a folder full of video looks different from a folder full of code. Click a block to go into it. The list below is the same thing, and works with a keyboard and a screen reader.
| Name | Size |
|---|
The single files taking the most room. Deleting one big file usually beats deleting a thousand small ones.
| File | Size |
|---|
Files with identical contents. Strata compares them byte for byte — same size, then a hash of the first 64 KB, then a hash of the whole file — so a renamed copy is still caught and two different files are never called the same.
Folders whose contents a tool can recreate from what is already on disk, like
node_modules or a build directory. This is a match on the folder's
name, not proof — check before you act.
Where the space goes by kind of file.
| Kind | Size | Share |
|---|
Large files you have not modified in over a year. Old is not the same as unwanted — this is a shortlist to look through, nothing more.
| File | Size | Last modified |
|---|
Strata does not delete anything, so the useful thing to leave with is a list. Export it, then act in your own file manager where deletions go to the Trash and can be undone.
Every disk cleaner is a list of promises about your files. These are the ones Strata refuses to make.
A browser can only delete permanently — it cannot move anything to the Trash. A cleaner with no undo is not worth the gigabytes, so this page shows and counts, and you delete where the Trash still protects you. The Windows app can clean up, because it can use the Recycle Bin.
Removing an app's leftovers means editing the Windows registry or reaching into ~/Library. Guessing at that is how a cleaner breaks the software you still use.
No CPU, memory or network graphs. A browser cannot read them, so any web page showing you those numbers is showing you something else.
Operating systems hide some folders from the browser. Anything Strata was refused is counted and named, and the total is labelled a floor rather than a truth.
No. There is no server and no account. File names, paths, sizes and contents are read into the tab and never sent anywhere — put the page in your browser's network tab and watch it, or load the page and then turn off your network; everything still works.
For honesty, the one exception has nothing to do with your files: like every page here, opening it sends a single anonymous "a page was opened" ping so I know whether anyone uses this. It carries no identifier and nothing about your disk, it honours Do Not Track and Global Privacy Control, and blocking it changes nothing about how Strata works.
If you would rather not take any of that on trust, download the file and run it from your own disk. That copy has the counter stripped out and makes no requests whatsoever.
Chrome, Edge, Brave, Opera and Arc get the full experience through the File System Access API, including re-reading a folder after you have cleaned it up.
Firefox and Safari do not have that API yet, so Strata falls back to the classic folder picker. Every measurement, the map, duplicates and exports all still work — you just pick the folder again each time instead of re-scanning in place.
Browsers refuse access to the root of a system drive and to sensitive folders like
Library, Windows and System. That restriction is the
reason this is safe to run, so Strata works with it rather than around it: point it at your
home folder, your Downloads, an external drive or a projects directory.
Mostly caches, local snapshots, logs and sleep/swap files that macOS manages itself. Strata can measure any of it you can open, but a lot of it lives in protected locations, and the honest answer is that a browser cannot see all of it. If that number is your problem, this tool will help with the part of it that lives in your home folder, and not the rest.
Two files called invoice.pdf may be different, and IMG_0421.jpg and
IMG_0421 (copy).jpg may be identical. Strata never trusts the name: it groups
by exact size, hashes the first 64 KB of every candidate, then hashes the whole file for
anything still matching. Files are only reported as duplicates when every byte agrees.
Usually, but Strata only matched the folder's name against a list of well-known build and dependency directories — it has not verified that a project can actually rebuild. Each entry says what recreates it. Treat the tab as a shortlist to review, not an instruction.