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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