The most common prefix system used is the Denary(Decimal) Prefix system. This is the system we use every day: Kilogram, Megabyte, Kilometer.
The denary prefix system works by each prefix being 1000 times larger than the previous prefix:
Unit
Value
Power of 10
1 Kilobyte (KB)
1000 Bytes
103
1 Megabyte (MB)
1000 Kilobytes (KB)
103
1 Megabyte (MB)
1,000,000 Bytes
106
1 Gigabyte (GB)
1000 Megabytes (MB)
103
1 Gigabyte (GB)
1,000,000,000 Bytes
109
1 Terabyte (TB)
1000 Gigabytes (GB)
103
1 Terabyte (TB)
1,000,000,000,000 Bytes
1012
Sometimes you will see sizes shown in bits(b), instead of bytes(B), especially when talking about network speeds:
20 Mbps = 20 Megabits per second (notice the small b?)
What is the denary (decimal) prefix for 1000?
The prefix mega represents 1000000
Which is typically used to measure internet speed?
Which is typically used to measure file size?
When using decimal prefixes, calculations involve powers of
Conversion between Binary and Denary (Binary & Denary Prefixes)
Binary Prefixes – Kibi / Mebi / Gibi / Tebi
This works well where we humans count in denary (Powers of 10) but computers count in binary (Powers of 2) and therefore we need to use a binary prefix instead – Kibi, Mebi, Gibi, Tebi
Unit
Value
Power of 2
1 Kibibyte (KiB)
1024 Bytes
210
1 Mebibyte (MiB)
1024 Kibibytes (KiB)
220
1 Mebibyte (MiB)
1,048,576 Bytes
220
1 Gibibyte (GiB)
1024 Mebibytes (MiB)
230
1 Gibibyte (GiB)
1,073,741,824 Bytes
230
1 Tebibyte (TiB)
1024 Gibibytes (GiB)
240
1 Tebibyte (TiB)
1,099,511,627,776 Bytes
240
Binary & Denary comparison table
Here we can see the binary and denary prefixes side by side.
Decimal Prefix
Decimal Value
Binary Prefix
Binary Value
kilo- (k)
10^3 (1,000)
kibi- (Ki)
2^10 (1,024)
mega- (M)
10^6 (1,000,000)
mebi- (Mi)
2^20 (1,048,576)
giga- (G)
10^9 (1,000,000,000)
gibi- (Gi)
2^30 (1,073,741,824)
tera- (T)
10^12
tebi- (Ti)
2^40
The binary prefix represents 1048576
When using binary prefixes, calculations involve powers of
