TreeSize Free for PC: How to Download and Install on Windows (2026 Guide)

Windows flashes the “low disk space” warning, Settings shows a vague bar of coloured blocks, and you are left guessing which folder is responsible. Deleting files blind is risky — the biggest space thief is usually something you forgot existed, buried three folders deep.

This guide shows you how to download TreeSize Free for PC from the official JAM Software website, install it on Windows 11 or 10, and scan a drive to find its biggest folders — plus key features, system requirements and an honest Free versus Professional comparison.

What Is TreeSize Free?

TreeSize is a disk space manager from JAM Software, a German developer that has refined it for decades. The Free edition scans any drive or folder and displays the results as an Explorer-style tree, every folder labelled with the total size of everything inside it — so you start at the full drive and drill down, level by level, to the folder eating your space.

It reads like the File Explorer you already know — no new interface to learn. Alongside the tree, a treemap chart shows big folders as big tiles, details columns report file counts, allocated space and last-change dates, and sorting by size puts the worst offenders on top. A portable version exists for USB-stick diagnostics.

Key Features of TreeSize Free

Explorer-style size tree: Every folder shown with its total size, so you drill straight to the problem.
Treemap chart: A visual map where the biggest folders are the biggest tiles — space hogs at a glance.
Rich details: Size, allocated space, file counts and last-modified dates for every entry.
Sort and filter: Rank everything by size instantly, or focus scans on a single folder.
Accurate accounting: Handles NTFS compression and hardlinks correctly, so reported sizes are trustworthy.
Context-menu launch: Right-click any folder in Explorer and scan just that folder in TreeSize.
Portable version: Run TreeSize Free from a folder or USB stick, no install needed.

System Requirements

Operating System: Windows 11 or Windows 10
Processor: Any modern Intel or AMD CPU
RAM: 2 GB recommended for very large drives
Storage: Around 25 MB for the program
Internet: Only for the initial download
Account: None for the Free edition; a licence key is entered only for Professional
Permissions: Administrator rights let TreeSize read protected folders for a complete scan

How to Download TreeSize Free (Official Method)

Disk tools attract copycat pages, and an unofficial “TreeSize” installer can bundle anything. Download TreeSize Free only from the official JAM Software website linked below, where the developer publishes the Free edition.

Official Website: Download TreeSize Free from the official website

Step-by-Step Installation

Open the official TreeSize page linked above and find the Free edition download.
Click the Free download button and save the installer, named like TreeSizeFreeSetup.exe, to your Downloads folder.
Double-click the installer and approve the Windows permission prompt.
Choose your language and accept the licence agreement.
Keep the default installation folder and click Next through the options.
Click Install, then Finish.
Launch TreeSize Free from the Start menu — or right-click any folder in Explorer and choose the TreeSize option.

First-launch note: For a complete picture of your system drive, run TreeSize Free as administrator: right-click its icon and choose “Run as administrator”. Without it, Windows hides protected folders and totals under-report the drive.

How to Scan a Drive and Find the Biggest Folders with TreeSize Free

Open TreeSize Free (as administrator) and click “Select Directory” or pick a drive from the ribbon’s drive list.
Choose your system drive (usually C:) and let the scan run — results update live.
In the tree, folders are already sorted by size: the top entry is your biggest space user.
Click the + beside the biggest folder to expand it, and keep drilling down to the subfolder responsible.
Switch to the “Treemap” view if you prefer a visual map of the same results.
Note the culprits — old games, forgotten downloads, video folders — then clean up through Explorer or each program’s own uninstaller.

TreeSize Free vs Professional: What Is the Difference?

The Free edition is a complete disk-space finder for a single PC: local drive and folder scans, the size tree and treemap, details columns and Explorer integration, free of charge with no expiry date. Professional is the paid edition for administrators and larger environments. It adds network drive and SharePoint scanning, scheduled and command-line scans, file search with duplicate finding, and report exports to Excel and PDF. For answering “what filled my drive?” on your own computer, Free honestly does the whole job — Professional is for people who audit many machines.

Frequently Asked Questions

Is TreeSize Free safe to download and use?
Yes, from the official JAM Software website linked above. TreeSize is long-established professional software, and the Free edition only reads and reports on your files — it deletes or moves nothing on its own. The care is in what you choose to delete afterwards: use it to find candidates, and remove programs through their uninstallers.

Is TreeSize Free really free, or is it a trial?
It is genuinely free — a permanent free edition, not a trial that expires or nags you into paying. JAM Software sells Professional for network scanning, scheduling and reporting, but the Free version’s local scanning is the full feature for home use.

What is the difference between TreeSize Free and WinDirStat or WizTree?
All three answer the same question for free. WinDirStat is the open-source classic with a famous treemap but slower scans. WizTree is the speed champion on NTFS drives. TreeSize Free sits between them: an Explorer-familiar interface, careful NTFS accounting and a polished treemap. Any of them will find your missing gigabytes.

Why should I run TreeSize as administrator?
Ordinary accounts cannot read certain protected locations, such as other users’ folders and parts of the Windows directory, so scans skip them and your drive’s total looks smaller than reality. Running as administrator lets TreeSize measure everything — the honest, complete picture.

Conclusion

TreeSize Free answers the most annoying storage question — “where did all my space go?” — in one clear, sortable tree. Download it free from the official JAM Software website, scan as administrator, and follow the numbers straight to the folder hiding your gigabytes.

Download TreeSize Free from the Official Website

TreeSize Free for PC: How to Download and Install on Windows (2026 Guide)