Toolcroft

Data Storage Converter (KB, MB, GB, TB)

Unit Converters

Convert bits, SI bytes, and IEC units from KiB through EiB. Compare KB with KiB and GB with GiB, and estimate download times. Free and browser-based.

KB vs KiB: KB (SI) = 1,000 bytes; KiB (IEC) = 1,024 bytes. Hard drives use decimal; operating systems often report in binary.
Try:

1 GB × (1000000000 / 1073741824) = 0.931323 GiB

Size in context (log scale)

1 B
1 KB
1 MB
1 GB
1 TB
1 PB
1 EB

All units

Bits (decimal)

  • Bit (b)8000000000
  • Kilobit (kb)8000000
  • Megabit (mb)8000
  • Gigabit (gb)8
  • Terabit (tb)0.008

Bytes (SI / decimal)

  • Byte (B)1000000000
  • Kilobyte (KB)1000000
  • Megabyte (MB)1000
  • Gigabyte (GB)1
  • Terabyte (TB)0.001
  • Petabyte (PB)0.000001
  • Exabyte (EB)1e-9

Bytes (IEC / binary)

  • Kibibyte (KiB)976563
  • Mebibyte (MiB)953.674
  • Gibibyte (GiB)0.931323
  • Tebibyte (TiB)0.000909495
  • Pebibyte (PiB)8.88178e-7
  • Exbibyte (EiB)8.67362e-10

Estimate download time

Ideal time = file size in bits ÷ connection speed in bits per second.

Ideal download time: 40 seconds

Real downloads often take 20–50% longer due to protocol overhead, congestion, and server limits.

How to use this tool

  1. Enter a value. Type the amount of data you want to convert in the "From" field.
  2. Select source unit. Choose the unit you are converting from - bits, bytes (SI), or binary IEC units.
  3. Select target unit. Choose the unit you want to convert to. The result updates instantly.
  4. Copy the result. Click the copy button next to the result field to copy it to your clipboard.
  5. Compare units or estimate a transfer. Review the all-units panel or enter a file size and connection speed to estimate ideal download time.

MB vs MiB: what's the difference?

Two systems define storage prefixes. The SI (decimal) system, used by hard drive manufacturers and internet speeds, defines 1 KB = 1,000 bytes. The IEC (binary) system, used by operating systems when reporting RAM and file sizes, defines 1 KiB = 1,024 bytes. The gap widens at larger sizes:

Common storage conversions

ValueResult
1 byte (B)8 bits
1 KB1,000 bytes (decimal)
1 KiB1,024 bytes (binary)
1 MB1,000,000 bytes
1 MiB1,048,576 bytes
1 GB1,000,000,000 bytes
1 GiB1,073,741,824 bytes
1 TB1,000,000,000,000 bytes
1 TiB1,099,511,627,776 bytes
1 PB1,000,000,000,000,000 bytes
1 PiB1,125,899,906,842,624 bytes
1 TB≈ 0.9095 TiB
1 Gbps125 MB/s
1 Mbps0.125 MB/s

Why does my hard drive show less space?

A 1 TB hard drive stores exactly 1,000,000,000,000 bytes. Windows reports storage using binary GiB, so it shows roughly 931 GiB (≈ 931 "GB" in Windows terms) instead of 1,000 GB. The drive is not defective; it's a units mismatch.

The binary vs. SI gap

The further up the prefix scale you go, the larger the discrepancy between SI and binary:

SI sizeBinary equivalentDifference
1 KB (1,000 B)0.977 KiB−2.3%
1 MB (1,000,000 B)0.954 MiB−4.6%
1 GB (10⁹ B)0.931 GiB−6.9%
1 TB (10¹² B)0.909 TiB−9.1%
1 PB (10¹⁵ B)0.888 PiB−11.2%

Download time calculator

To estimate download time: time (seconds) = file size (bits) / speed (bits per second). Example: A 500 MB file over 100 Mbps connection:

  • 500 MB × 8 = 4,000 Mb (megabits)
  • 4,000 Mb / 100 Mbps = 40 seconds (ideal)
  • Real-world: +20–50% overhead from protocol headers, congestion, etc.

RAID storage considerations

RAID arrays consume more raw disks than usable capacity due to redundancy:

  • RAID 1 (mirroring): 50% efficiency. 2 × 1 TB = 1 TB usable.
  • RAID 5: (n−1)/n efficiency. 4 × 1 TB = 3 TB usable (one disk for parity).
  • RAID 6: (n−2)/n efficiency. 6 × 1 TB = 4 TB usable (two parity disks).
  • RAID 10: 50% efficiency like RAID 1, but with striping for performance.

Real-world file size examples

  • High-quality MP3: ~1 MB per minute (320 kbps)
  • FLAC audio: ~30 MB for a 3-minute song (~1000 kbps)
  • 1080p video (H.264): ~5 GB per hour (high bitrate)
  • 4K video (H.265/HEVC): ~8–15 GB per hour
  • RAW photo (24 MP): 25–50 MB per image
  • JPEG photo (24 MP): 5–10 MB per image
  • Modern AAA game: 50–150 GB installed

The IEC introduced the “ibibyte” prefixes (KiB, MiB, GiB, and larger units) to distinguish powers of 1,024 from the SI powers of 1,000. Operating systems and software have adopted those labels at different rates, so checking whether a value is decimal or binary still matters when comparing drive labels, file sizes, and memory capacity.

Frequently asked questions

What is the difference between KB and KiB?

KB (kilobyte) uses the SI (decimal) definition: 1 KB = 1,000 bytes. KiB (kibibyte) uses the IEC (binary) definition: 1 KiB = 1,024 bytes. The difference grows at higher prefixes - 1 GB = 1,000,000,000 bytes, while 1 GiB = 1,073,741,824 bytes (about 7% more).

How many bytes are in a megabyte?

In the SI (decimal) system, 1 MB = 1,000,000 bytes. In the IEC (binary) system, 1 MiB = 1,048,576 bytes. Hard drive manufacturers use the decimal system (1 MB = 1,000,000 bytes), while operating systems often report sizes using binary units - which is why a "500 GB" hard drive appears as roughly 465 GB in Windows.

How many bits are in a byte?

There are exactly 8 bits in 1 byte. A bit is the smallest unit of digital data (0 or 1). Internet speeds are typically measured in bits per second (Mbps), while file sizes use bytes.

How do I convert MB to GB?

Divide the value in megabytes by 1,000 to get gigabytes (SI). For example, 5,000 MB = 5 GB. If using binary units, divide mebibytes by 1,024 to get gibibytes: 1,024 MiB = 1 GiB.

Why does my hard drive show less storage than advertised?

Hard drive manufacturers measure in decimal (1 GB = 1,000,000,000 bytes), but operating systems like Windows report storage in binary units (1 GB = 1,073,741,824 bytes). A 1 TB drive has exactly 1,000,000,000,000 bytes, which Windows reports as approximately 931 GiB.

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