IEC Prefixes

Vali-FileSize supports the full IEC 80000-13 binary prefix standard alongside traditional binary units.

Background

Both traditional (KB, MB, GB…) and IEC (KiB, MiB, GiB…) units use a base of 1 024. The difference is purely in the suffix:

Traditional	IEC	Factor
KB	KiB	1 024 B
MB	MiB	1 024 KiB
GB	GiB	1 024 MiB
TB	TiB	1 024 GiB
PB	PiB	1 024 TiB
EB	EiB	1 024 PiB

Using IEC prefixes

Pass useIec: true to GetBestUnit and FormatBestSize:

var vfs = new ValiFileSize();

// FormatBestSize
vfs.FormatBestSize(1_073_741_824, useIec: true);  // "1.00 GiB"
vfs.FormatBestSize(1_073_741_824);                 // "1.00 GB"

// GetBestUnit
var (size, unit) = vfs.GetBestUnit(1_073_741_824, useIec: true);
// size → 1.0, unit → FileSizeUnit.Gibibytes

// Extension methods
1_073_741_824.0.FormatBestSize(useIec: true);   // "1.00 GiB"
1_073_741_824L.GetBestUnit(useIec: true);        // (1.0, FileSizeUnit.Gibibytes)

Explicit IEC units with Convert and FormatSize

You can also use IEC enum values directly:

// Convert using IEC units
double mib = vfs.Convert(1, FileSizeUnit.Gibibytes, FileSizeUnit.Mebibytes); // 1024

// Format an IEC unit
vfs.FormatSize(1024, FileSizeUnit.Mebibytes); // "1024.00 MiB"