For an LBA-to-byte calculation, use LogicalBytesPerSector from the relevant storage view. Do not substitute a physical-sector value or the NTFS cluster size just because it also says 4096.
The fsutil fsinfo sectorinfo command reports several related values. A drive can expose 512-byte logical sectors and 4096-byte physical sectors at the same time; that is the familiar 512e arrangement.
Read the values as information reported through the current storage stack. Enclosures, controllers, virtual disks, and unavailable device information can limit what they prove about the underlying hardware.
Run the query for the intended volume
Open Command Prompt as administrator. After confirming the target in Disk Management, run:
fsutil fsinfo sectorinfo D:
Replace D: with your confirmed local volume. This queries information; it does not change sector size, format the volume, repair it, or request a restart.
Keep the complete output before selecting individual lines. If the query fails, preserve the error message. A failed query is not a zero-byte sector size.
If the volume is locked, inaccessible, or part of a more complex storage arrangement, resolve the access or identification question before using a value in a calculation.
Which field answers which question?
Logical addressing block size
LogicalBytesPerSector
The size of a logical addressing block. Use this value to convert an LBA into bytes in the same address space.
Physical write unit
PhysicalBytesPerSectorForAtomicity
The reported physical sector size for atomic writes. Use it to understand the reported write unit.
Physical performance unit
PhysicalBytesPerSectorForPerformance
The reported sector-size unit for best performance. This is useful for application I/O planning.
Effective physical unit used by the file system
FileSystemEffectivePhysicalBytesPerSectorForAtomicity
The physical-sector value the file system treats as effective. Use it to understand the file system’s view.
The physical fields are not interchangeable with the logical one. They answer different questions.
“Atomicity” here describes a reported storage unit. It is not a guarantee that an entire application transaction survives every power failure. “Performance” is also not a measured transfer speed.
Alignment information concerns boundaries. An alignment offset is not the absolute starting byte of the partition; do not use it as the partition offset in a disk-to-volume conversion.
How 512n, 512e, and 4Kn differ
The common arrangements are:
| Arrangement | Logical bytes per sector | Physical bytes per sector |
|---|---|---|
| 512n | 512 | 512 |
| 512e | 512 | 4096 |
| 4Kn | 4096 | 4096 |
These rows describe the standard formats. The conclusion you can draw from a particular query still depends on whether the device and driver are reporting the underlying values accurately.
For example, this is illustrative output, not a measurement from a tested drive:
LogicalBytesPerSector : 512
PhysicalBytesPerSectorForAtomicity : 4096
That pair is consistent with 512e reporting. It means an LBA calculation in this storage view uses 512 bytes per logical sector.
A 512/512 result needs more caution when identifying physical media. Microsoft’s sector-information structure can fall back to the logical value when physical-sector information cannot be determined. A matching pair therefore does not always establish that the underlying device is physically 512n.
If fields disagree, are unavailable, or are unexpected for the product, keep the raw output and consult the device or controller documentation. Do not silently change the values until they fit one row.
Show only two lines in PowerShell
When reading several reports, you can retain the original output and then filter it. Open Windows PowerShell as administrator, replace D: with the confirmed local volume, and run:
$sectorInfo = & fsutil fsinfo sectorinfo D:
if ($LASTEXITCODE -ne 0) {
throw 'sectorinfo failed. Review the original error.'
}
$sectorInfo
Then, in the same session:
$sectorInfo |
Select-String -Pattern '^\s*(LogicalBytesPerSector|PhysicalBytesPerSectorForAtomicity)\s*:'
The expression selects those two English field names at the beginning of a line. It avoids accidentally selecting the longer file-system-effective field.
If your Windows output uses different labels, the filter can return nothing even though the full query succeeded. Read $sectorInfo directly and use the labels actually shown. This is a display filter, not a language-independent parser or a health test.
Do not discard the full output just because the two-line view is easier to copy.
Use the value in the right calculation
Suppose an illustrative LBA is decimal 2048:
| Logical sector size | Calculation | Byte offset |
|---|---|---|
| 512 bytes | 2048 × 512 | 1,048,576 |
| 4096 bytes | 2048 × 4096 | 8,388,608 |
Using 4096 when the address actually counts 512-byte logical blocks gives an answer eight times too large. The physical sector size does not correct that mistake.
For a complete decimal and hexadecimal calculation, see LBA to Byte Offset: Decimal, Hex, and Sector Size.
Also confirm what the LBA is relative to. An address in a disk event, a virtual disk, and a file-system utility may not describe the same origin or storage layer.
A sector-size query on C: is useful only if C: belongs to the same relevant device view as the address you are interpreting. It cannot automatically supply the block size for another disk or a hidden RAID member.
Sector size is not cluster size
NTFS groups storage into allocation units called clusters. A 4096-byte cluster can exist on a volume with 512-byte logical sectors. In that example, one cluster spans eight logical sectors.
To inspect NTFS-specific information, use fsutil fsinfo ntfsinfo against the confirmed NTFS volume from an elevated command prompt and look for the cluster-size field. Do not substitute that value for LogicalBytesPerSector.
Once you have the correct device view, logical sector size, and address origin, preserve them together with the original address. Those details make the calculation reproducible and prevent a plausible-looking number from referring to the wrong location.
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