Digital Metric Unit Nomenclature for Dummies
Written: 2024-01-03 · Last Updated: Never
This is a rewrite of a Google Doc I made in December, I decided to publish it because some (Windows users) people need to know…
Metric Prefixes
Nano- to Yotta- scale, excluding middle values where the absolute of the scale is < 10-3.These are increments of 1,000. Kilo- means 1,000, Giga- means 1,000,000,000, Peta- means 1,000,000,000,000,000, etc.
| Prefix | Nano | Micro | Milli | Kilo | Mega | Giga | Tera | Peta | Exa | Zetta | Yotta |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symbol | n | µ | m | k | M | G | T | P | E | Z | Y |
| Quantity | 1/109 | 1/106 | 1/103 | 103 | 106 | 109 | 1012 | 1015 | 1018 | 1021 | 1024 |
Binary Prefixes
Same scale, same exclusionsThese are increments of 1,024 (210). Kibi- means 1,024, Gibi- means 1,073,741,824, Pebi- means 1,125,899,906,842,624, etc.
| Prefix | Nanobi | Microbi | Millibi | Kibi | Mebi | Gibi | Tebi | Pebi | Exbi | Zebi | Yobi |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Symbol | ni | µi | mi | Ki | Mi | Gi | Ti | Pi | Ei | Zi | Yi |
| Quantity | 1/1,0243 | 1/1,0242 | 1/1,024 | 1,024 | 1,0242 | 1,0243 | 1,0244 | 1,0245 | 1,0246 | 1,0247 | 1,0248 |
Units
| Unit | Bit | Byte |
|---|---|---|
| Description | A bit is a singular 1 or 0. A yes or a no. True or false. 0111011110001 is an example of 13 bits. | A byte is a set of 8 bits. 01101000 01101001 is an example of 2 bytes, 16 bits in total. |
| Symbol | b | B |
Suffixes
The most common suffixes used are for rates of data being transferred in the period of 1 second.
| Unit | Bits per Second | Bytes per Second |
|---|---|---|
| Description | The number of bits transferred in the span of a second. | The number of bytes sent in 1 second. |
| Symbol | ps | /s |
Combining
A prefix to denote quantity and a unit to describe what is actually being talked about are all that’s required. A rate over time can also be suffixed.
For example:
| Name | Notation | Numerical Meaning |
|---|---|---|
| Megabytes per Second | MB/s | 1,000,000 bytes (8,000,000 bits) sent in a second. |
| Megabits per Second | Mbps | 1,000,000 bits (125,000 bytes (125 kB)) transferred in a second. Usually used by ISPs to make rates look faster; your 100 Mbps internet is only ~11.921 MiB/s. |
| Mebibytes per Second | MiB/s | 1,048,576 bytes (8,388,608 bits) transferred in a second. Often used to denote file download speeds, sometimes (although not always) mislabeled or said as MB/s. |
Sources
- Wikipedia – Metric prefix
- Wikipedia – Binary prefix
- Ext4 filesystem on my computer.
- A YouTube video I saw once confirming that Windows labels things “KB,” “MB,” and “GB” despite 1. “KB” not being a valid unit (should be “kB”), and 2. displaying values for the kilo-, mega-, and giga- (etc) values using multiples of 1,024 and not 1,000 (suggesting that the correct labels should be KiB, MiB, GiB, etc).