Is my SMART data uploaded anywhere?

No. The decoder parses the text you paste entirely in your browser tab. There is no upload — you can confirm it in your browser's DevTools Network panel: pressing Decode makes no network request.

Can it tell me if my drive is about to fail?

No — and neither can any tool honestly. It reports the numbers and explains what's normal, and flags real warning signals (reallocated sectors, media errors, available spare at or below its threshold). It never issues a pass/fail verdict or predicts a failure date.

Why does my Apple Silicon Mac show so little SMART data?

Apple-Silicon internal SSDs generally do not expose the full NVMe SMART health log to the OS, so macOS's system_profiler only shows a basic SMART status. That's an Apple limitation, not a fault with your drive.

SMART / NVMe decoder

Paste your drive's SMART data. Get plain English.

Run one command, paste the output, and see what the attributes that matter mean — TBW, life used, available spare, media errors, power-on hours — each with what's normal. It decodes the key health attributes (not every vendor-specific one). Works for smartctl (NVMe & SATA) and macOS system_profiler.

Parsed in this tab — nothing is uploaded. Verify it yourself: open DevTools → Network, then press Decode. No request fires.

try a sample:

How to get your SMART data

You need smartctl from smartmontools (brew install smartmontools). Then, for most drives:

smartctl -a disk0 — full attributes (swap disk0 for your drive; diskutil list shows them).
On an Apple-Silicon internal SSD, also try system_profiler SPNVMeDataType — macOS exposes only a basic SMART status there (see below).

Paste the whole thing into the box above. It never leaves your browser.

What the key attributes mean

Percentage Used (NVMe): The controller's own estimate of how much rated write endurance is spent. It's a wear gauge, not a countdown — it can pass 100% and the drive keeps working.
Data Units Written → TBW: Lifetime host writes. One NVMe data unit = 1,000 × 512 bytes, so TB written = data-units × 512,000 ÷ 10¹². Compare it to your drive's rated TBW (on its spec sheet).
Available Spare + Threshold: Reserve flash blocks used to replace worn ones. Healthy drives sit near 100%; a value at or below the threshold is a real signal to back up and plan a replacement.
Media & Data Integrity Errors: Unrecovered integrity errors. You want zero; a non-zero, rising count is worth watching.
Reallocated / Pending / Uncorrectable sectors (SATA): Retired, unstable, or unreadable sectors. Any of these above zero is a real warning sign on a SATA SSD or hard drive.
Power-On Hours & Cycles: How long, and how many times, the drive has been powered. Context for the wear numbers — ~8,760 h is a year of 24/7.

Why Apple Silicon Macs show so little

Apple-Silicon internal SSDs generally don't expose the full NVMe SMART health log to macOS, so system_profiler shows only a basic SMART Status: Verified — not Percentage Used or Data Units Written. That's an Apple design choice, not a fault. External USB/Thunderbolt NVMe enclosures often do pass the full log through, so smartctl can read it there.

What this tool will never do

It will never tell you your drive is "failing", "genuine", or "counterfeit", and it will never give you a failure date — no honest tool can. Drive health is a trend you watch, not a verdict. This decoder reports the numbers, explains them, and flags the handful of attributes that are real warning signs. That's the same honest posture CoreGuard takes in the app: it observes and explains, and every hardware-danger warning is free.