Which fits your needs?
JDiskReport: Users who want cross-platform disk statistics and already use Java.
WhatSize: Mac users who favor column browsing and integrated duplicate/cleanup tools.
Features, pricing, and workflow
Scroll across to compare
| Feature | JDiskReport | WhatSize |
|---|---|---|
| Best fit | Users who want cross-platform disk statistics and already use Java. | Mac users who favor column browsing and integrated duplicate/cleanup tools. |
| Visualization | Overview statistics charts and detail tables | Size-sorted columns and measurement views |
| Platforms and requirements | macOS, Windows, Linux (Java) | macOS 11+ (current vendor requirements) |
| Pricing and editions | No-charge, ad-free freeware; this does not mean open source. | Vendor lists $14.99 and a 30-day trial; upgrades may be priced separately. |
| Open source | No | No |
| Native macOS UI | Cross-platform interface | Yes |
| Cleanup workflow | Use the statistics to guide file review; the cited overview does not specify removal semantics. | Review the chosen cleaning or duplicate action before applying it. |
| Reports and portability | Preserve any saved scan files supported by your version and keep important table entries. NullDisk does not import JDiskReport scan files. | Preserve any saved measurements or reports supported by your version. The cited overview does not establish an import format shared with NullDisk. |
JDiskReport: what stands out
A good fit for users who want cross-platform disk statistics and already use Java.
JDiskReport: strengths
- Disk usage statistics in charts and tables
- Runs across Java-capable desktop systems
- Free without ads or expiry
Considerations
- Requires a compatible Java runtime
- Freeware rather than an open-source project
- Check the manual for report storage and file-management actions
WhatSize: what stands out
A good fit for Mac users who favor column browsing and integrated duplicate/cleanup tools.
WhatSize: strengths
- Size-sorted columns and detailed filtering
- Duplicate-file tools and cleanup categories
- Updates measurements as the filesystem changes
Considerations
- Paid license after the trial
- Cleanup categories still require your judgment
- Check upgrade terms separately from the initial purchase
For a useful comparison on your own drive, match the scan root, access permissions, and size mode. Chart style changes how you explore the results; it does not by itself establish measurement accuracy.
Common questions
When should I choose JDiskReport?
A good fit for users who want cross-platform disk statistics and already use Java. No-charge, ad-free freeware; this does not mean open source.
When should I choose WhatSize?
A good fit for Mac users who favor column browsing and integrated duplicate/cleanup tools. Vendor lists $14.99 and a 30-day trial; upgrades may be priced separately.
Will both apps show the same size?
Not necessarily. Match the scan root, permissions, exclusions, and logical/allocated-size mode. Hard links, APFS clones, snapshots, sparse files, and cloud placeholders can change totals. A reported size is not a guaranteed amount recovered after deletion.