Grading
Grading key
Grades here are defined by numbers you can check on the drive when it arrives, not by adjectives. "Excellent condition" means nothing. Reallocated sectors: 0 means something.
The key
Every line has to pass. A drive that fails a single one of them is not sold, and is not relisted at a lower grade.
| Grade | Reallocated | Pending / uncorrectable | Surface pass | Health |
|---|---|---|---|---|
| A Grade | 0 | 0 / 0 | Pass | 95-100% |
| B Grade | 1 - 8, stable | 0 / 0 | Pass | 85-94% |
| C Grade | 9 - 24, stable | 0 / 0 | Pass | 75-84% |
| Reject Grade | rising | any | Fail | under 75% |
Swipe the table to see every column
A drive is rejected outright on any pending sector, any uncorrectable sector, a reallocation count that rises between readings, or a failed surface pass. Rejected drives do not go back into stock. This is the whole point of having a key.
On reallocated sectors
A reallocated sector is one the drive found unreadable and swapped for a spare from its reserve pool. Grade A means zero of them.
Pending and uncorrectable sectors are different, and we treat them differently. A pending sector is one the drive could not read and has not yet reallocated, which makes it an active fault rather than wear. Any pending sector or any uncorrectable error rejects a drive outright, at every grade. Those two are not a matter of degree.
On health percentage
Health is a composite that Hard Disk Sentinel calculates from the underlying attributes. It is not stored on the drive and it is not a manufacturer figure. It is useful because it is legible at a glance. The raw counts are the ones to trust, and they are on the reading we hold for your serial.