Byte Size Calculator

Convert between bytes, kilobytes, megabytes, and more. Understand the difference between SI (decimal, 1 KB = 1,000 B) and binary/IEC units (1 KiB = 1,024 B).

ℹ️1 byte = 8 bits. Network speeds are measured in bits (Mbps), storage in bytes (MB).
Enter a value
= 100,000,000 bytes
Common sizes — click to set
SI Units (1 KB = 1,000 B)
Bitbit800,000,000
ByteB100,000,000
KilobyteKB100,000
MegabyteMB100
GigabyteGB0.100
TerabyteTB0.000100
PetabytePB0
ExabyteEB0
Binary / IEC Units (1 KiB = 1,024 B)
KibibyteKiB97,656.25
MebibyteMiB95.367431
GibibyteGiB0.0931
TebibyteTiB0.0000900
PebibytePiB0
ExbibyteEiB0
SI vs Binary — what's the difference?
SI (Decimal)
1 KB = 1,000 bytes
1 MB = 1,000,000 B
1 GB = 1,000,000,000 B
1 TB = 1012 B
IEC (Binary)
1 KiB = 1,024 bytes
1 MiB = 1,048,576 B
1 GiB = 1,073,741,824 B
1 TiB = 240 B
Why does this matter? Hard drive manufacturers use SI (decimal) units — a "1 TB" drive holds 1,000,000,000,000 bytes. Operating systems often display binary (IEC) sizes — macOS and Linux report the same drive as ~931 GiB. This mismatch explains why your new drive appears "smaller" than advertised.
Transfer time calculator
SpeedConnectionTime to transfer
1 Mbpsslow internet13 minutes 20 seconds
100 Mbpstypical broadband8.0 seconds
1 Gbpsgigabit fiber0.800 seconds
10 Gbpsdata center0.080 seconds