PatternFly

Units and symbols

Communicating measurements

Use consistent formatting, terminology, and symbols when displaying units of measurement in your UI, including:

  • Currency.
  • Data bandwidth.
  • Data storage.
  • Time.

When displaying quantitative values for measurements in your UI, use the International System of Units (SI unit) so that your content can be understood by global users. The following table outlines the base units and symbols you should use to describe different quantitative values:

Measurement
Unit
Symbol
Length
Meter
m
Mass
Kilogram
kg
Electric current
Ampere
A
Thermodynamic temperature
Kelvin
K
Amount of substance
Mole
mol
Luminous intensity
Candela
cd

Currency

Wherever possible, display currency in three-letter code according to ISO Standard 4217. See our numerics guidelines for more information about writing currency.

Data bandwidth

Bandwidth is the amount of data transferred from one point to another within a network in a specified amount of time.

Data transfer is primarily measured in two ways:

  • Megabits/second (Mbps): Specifies download and upload speeds on the internet
  • Megabytes/second (MBps): Specifies the quantity of data or file size transferred over time

Data transfer rates can be measured in binary or metric units. Always align this unit with the scale you use to measure data size.

Binary unit
Symbol
1 mebibyte/second
MiBps
1 gibibyte/second
GiBps
1 tebibyte/second
TiBps
Metric unit
Symbol
1 megabyte/second
MBps
1 gigabyte/second
GBps
1 terabyte/second
TBps

Note: Pay special attention to the letter case when writing symbols for bits (b) and bytes (B). Eight bits (b) make up one byte (B), so using the wrong symbol will change your meaning.

Data storage

Computer storage and memory are typically measured in bytes. Bytes can be shown in binary units (gibibytes) or decimal/metric units(gigabytes).

To remain consistent and reduce confusion, use binary units to express amounts of digital information. This practice aligns with most computing and open source software.

Binary unit
Symbol
Value
1 kibibyte
KiB
1024
1 mebibyte
MiB
10242
1 gibibyte
GiB
10243
1 tebibyte
TiB
10244
Metric unit
Symbol
Value
1 kilobyte
KB
1000
1 megabyte
MB
10002
1 gigabyte
GB
10003
1 terabyte
TB
10004

Time

Whenever possible, write the full name of each time unit.

For example, write "6 minutes" instead of "6 min."

If space is limited, use symbols to communicate the same units of time in less space:

Unit
Symbol
Millisecond
ms
Second
s
Minute
min
Hour
h

Avoid using symbols for days, weeks, months, and years.

Best practices for writing units of measurement

Follow these general best practices for writing units of measurement:

Best practice
Examples
Use consistent units, and avoid mixing them.
Write 10 to 75 seconds instead of 10 seconds to 1.25 minutes.
Include a space between numbers and units, except for percentages.
Add a space to 75 kg but not to 75%.
Display the full name of each unit unless space is limited.
Write 6 seconds ago instead of 6s ago.
Don't make unit symbols plural.
Write 60 cm, not 60 cms.
Write SI unit symbols in lowercase. If a symbol is named after a person or proper noun, then capitalize its first letter.
Write W for watt.

Write Hz for hertz.
Don't mix symbols or apply mathematical operations to unit names.
Write kg/m3 instead of kilogram/m3.

Write kg · m-3 instead of kilogram/cubic meter.

Use kilogram per cubic meter instead of kg/cubic meter, kilogram per meter3, or kg per m3.
Use parentheses to display a secondary unit of measure.
10°C (50°F)
Clearly express units for two or more related quantities. If necessary, you can include the unit after each numeral.
Write 6 to 8 inches or 6 inches to 8 inches.
Use symbols to display derived units of measure (units formed using a calculation).
38 mph, 27 ft/s2
For derived units of measure, use the symbol that represents its word form, since it will be more familiar to your users.
Use Hz for Hertz instead of the derivation cycles per second (cycles/second).

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