Money saving apps for Mac are usually the phone app in a window, or a web page in a wrapper, and nearly all of them start by asking you to connect a bank account. Keep the Diff is a native macOS app, and it cannot connect to your bank because there is no bank integration in it at all.
What the app does
You log two numbers: what you were ready to spend, and what you actually spent. The difference is the Diff, and it is recorded as money you kept. The Diff adds up by week, by month, and toward whatever you are saving for.
Buy the thing anyway and nothing happens. There is simply no Diff that time. No budget to exceed, no streak to break, and no red number, because the lowest a week can read is zero.
On the Mac specifically
- A real Mac app, built with Compose Desktop and shipped as a normal DMG. Drag it to Applications and open it, and the install is done.
- Signed and notarized by Apple, so it opens without a Gatekeeper warning and without the right-click and Open workaround.
- The app updates itself. The download from this site checks for a new version and installs it, so you are not hunting for a DMG in six months.
- Lives in the menu bar. Open the app, log a Diff, visit this website, or report a bug or request a feature, all without switching windows.
- Premium can be bought right in the app. Click Premium, pick a plan, pay on Stripe's own page in your browser. Four plans, from $2.33 a month billed annually.
New in 1.2.7
- Premium Lifetime. Pay once for every Premium feature, now and later, on up to 10 devices.
- Sunday recap. Every Sunday at 6 pm, a short note of what you kept that week. You can turn it off in Settings.
- Rate and share. Rate Keep the Diff or share it with a friend, right from Settings.
- Sign in with Microsoft. Use your Microsoft account to sign in, so Premium follows you to every device.
Your numbers stay yours
No account needed, no analytics, no tracking and no advertising identifier. We never see anything you log. The app talks to the internet only if you buy or unlock Premium, which sends a short code and a receipt number, or if you turn on sync, which sends a copy sealed with a key only your devices hold.
What the app needs
macOS 12 or later. The app runs natively on Apple Silicon and on Intel Macs, and the download is signed and notarized by Apple with the ticket stapled to the file, so it opens on first launch without the right-click and Open dance.
Keep the Diff is a real Mac application. It opens without a browser, works with no connection, and keeps working if this website disappears tomorrow.
Installing the app
The download is a DMG. Open it, drag the app to Applications, and eject the disk image. The first launch may take a second longer than later ones while macOS checks the signature, which is normal and happens once.
The app checks for its own updates and tells you when one is ready, and no updater runs in the background when the app is closed.
Questions people ask before installing
Does the Mac app sync with my iPhone? Yes, with Premium, and only if you turn sync on. Unlock the Mac app with the code your iPhone gives you, then switch on Sync across your devices in Settings. Everything is encrypted on each device before it leaves, with a key we never have.
Is this the same app as the one in the App Store? It is the same application. Keep the Diff is on the Mac App Store, and the download on this page is the same build for anybody who prefers not to go through the store.
Is the free version time limited? No. Logging decisions, this week's total, your recent history and the weekly recap are free. Premium adds full history with export, categories, goals and App Lock.
Also on your other devices
The same app runs on iPhone, iPad, Apple Watch, Windows, Linux and Android. One Premium subscription covers every device you own, so buying it on the Mac unlocks the phone too.