Yesterday you had 162 GB. Today you have 148 GB.
DeltaDisk sits in the menu bar and tells you which folders took the difference — and which ones you can safely empty.
An example day. DeltaDisk measures your own folders once a day and keeps 30 days of history.
Download free trial Buy — $9.99
Free for 14 days with every feature. After that, the menu bar and cleanup stay free; Pro is $9.99, once. macOS 26 or later, Apple Silicon.
What it does
Shows the change, not the total
Every disk tool can tell you a folder is 40 GB. DeltaDisk tells you it grew 6 GB since yesterday — that's the part you can act on.
Lives in the menu bar
No Dock icon and no window to manage. Free space is always visible; click it when a number looks wrong.
Watches the folders you choose
Start with caches, Downloads and Application Support. Add a project folder or an external disk when you need to.
Keeps everything on your Mac
No account, no sign-in, no analytics. Nothing about your disks is ever sent anywhere.
A companion to disk scanners, not a replacement
| Full-disk scanners | DeltaDisk | |
|---|---|---|
| Best for | A snapshot of everything, right now | Watching what changes day to day |
| Runs | When you launch it | In your menu bar |
| You open it | When you're already out of space | Every day, for a second |
DeltaDisk doesn't replace a scanner. It shows you what changed day to day, so you know where to look before you reach for one.
Price
Free
Always free.
- Free space in the menu bar, with warning colors and notifications
- Cleanup: move safe-to-delete items to the Trash
- Daily scans of the 20 default folders
Pro — $9.99, once
Bought once, not a subscription.
- Growth tab: which folders grew since yesterday or last week, with a breakdown
- “Days until the warning line” forecast
- 30-day chart
- Add your own watched folders
Bought once, for up to 5 Macs you own. Every 1.x update is included.
Stripe handles payment and receipts. Refundable within 30 days. Or try every feature free for 14 days — no account needed.
Questions
I didn't receive my license key.
Check your spam folder first. You can also show the key again on the resend page using the email address you entered at checkout. If it still doesn't appear, email support@mossbit.app with that address.
Can I use it on more than one Mac?
Yes. One key works on up to 5 Macs that you own and use.
Why does it need Full Disk Access?
macOS hides the size of protected folders such as Mail and Messages unless you allow it. DeltaDisk measures folder sizes only. It never reads the contents of your files and never sends them anywhere.
What happens when the trial ends?
The menu bar, notifications and cleanup keep working for free. Pro features such as the growth tab unlock again when you register a license. Daily records continue in the meantime, so after you buy, the history is already there.
I changed my email address.
You can still use the old address on the resend page. To change the address on record, email support@mossbit.app.
How do I get a refund?
Within 30 days of purchase, no questions asked. See the refund policy.
Still stuck?
Write to support@mossbit.app. We answer within two business days.