Apple defines the number. Plainly gives you the verdict.
Your Mac's battery, explained like a human. A menu bar app that turns Apple's raw numbers into one calm, plain-English verdict. Read-only by design.
Apple's Battery Health pane will tell you your battery holds 87% of its original capacity. It won't tell you whether that's fine. Its "Learn More" link bounces you to a support website instead of answering the question you actually have, right there in front of you. Plainly reads the exact same numbers macOS already has and just says, in plain English, what they mean for you.
Example states, straight from the app's own test fixtures:
100% · 2 cycles — like new
There's nothing to know. You have a brand new laptop — don't worry about the battery at all yet.
87% · 412 cycles — normal
These batteries are built to still hold 80% after 1,000 cycles — so you're right on schedule. This is normal aging. You still have years of life left, and nothing to worry about.
79% · 950 cycles — worn
79 may seem alarming, but it's not an emergency. Nothing is broken or unsafe — it just runs out faster when unplugged. Replace it when that starts annoying you day to day.
62% · 1,310 cycles — service recommended
'Service Recommended' just means the battery holds much less charge than it used to. Nothing is failing — plugged in, it works exactly as normal. A new battery would make it feel young again; entirely up to you and your timing.
No battery detected
Nothing to watch here. No battery!
Plainly also watches for one habit in the moment: if you're plugged in and sitting at 100%, it'll gently note that macOS can cap charging at 80% to slow aging down — your call either way.
- Read-only. Plainly can't change anything about your battery or system settings — no charge limiting, no toggles. It only reads.
- No network calls. There's no networking code in this app at all — check the source, it isn't there.
- No analytics, no telemetry. Nothing is measured, collected, or sent anywhere.
- Open source. MIT licensed — read every line, including the rules table below.
Download the latest build from
Releases — unzip and
drag Plainly.app to Applications.
Because this build isn't notarized yet, macOS will warn you the first time. That's expected for a small open-source app without a $99 Apple Developer membership: right-click the app → Open → Open. You only do this once. (Everything the app does is in this repo — read it before you run it, that's the point of open source.)
Or build it yourself in about a minute:
git clone https://github.com/ovhirup/plainly.git
cd plainly
./Scripts/build-app.sh
open .build/Plainly.appRequires macOS 14+ on Apple Silicon, plus a Swift 6 toolchain (recent Xcode or Command Line Tools). Intel Macs are untested (different SMC keys) — PRs welcome.
A properly notarized, no-warning download is the goal — the $99 notarization fee makes sense once enough people want this. If Plainly told you something useful, a ⭐ on this repo or an email at https://tally.so/r/VLy5Nv is the vote that gets it there.
Quit from the "Quit Plainly" link at the bottom of the popover. If
that's ever unavailable, quit from Activity Monitor or killall Plainly instead.
Every verdict comes from a small, deterministic, human-readable rules
table in
Sources/Plainly/Battery/VerdictEngine.swift —
no ML, no server, no hidden logic. The core thresholds (a battery
designed to retain around 80% of its original capacity after roughly
1,000 complete charge cycles) come from
Apple's own published battery specifications.
Read the table, argue with it, or send a PR.
Plainly is meant to be a family, not a one-off. If read-only, plain-English explanation works for a battery, the next candidate is your Mac's heat and slowness — explained the same way. Issues, bug reports, and feedback are welcome.