Use a hyphen (-) when needed for clarity. A hyphen can separate parts of words to avoid misreadings, and it can combine terms when they should be read as a unit.
General guidelines
Guidance for hyphenation isn't always straightforward because it depends on the following circumstances:
- Location. For example, does a term precede a noun, or does it follow a verb?
- Interpretation and readability. Is a sentence ambiguous or unclear if a term is not hyphenated?
- Convention. For some terms, our guidance tells us to always hyphenate or never hyphenate, even if the convention seems to contradict other guidance.
In addition, there are many exceptions to general hyphenation guidance. If you're not sure whether to hyphenate a term, in addition to reviewing the guidelines on this page, check the following sources (in this order):
- The documentation that you're working with. If there's an established convention for hyphenating a term in a particular documentation set, follow that convention.
- The word list in this style guide.
- The Merriam-Webster dictionary.
As always, deviate from our guidance when it serves your readers. For more information, see Break the rules.
Prefixes
In general, don't use a hyphen between a prefix and the main noun.
Recommended: infrastructure, megabyte, metadata, preprocessing, pseudocode, semiconductor
Exceptions
Add a hyphen after a prefix in the following circumstances:
- If the prefix is self or cross: self-managing, cross-region
- If the noun is capitalized or is a number: non-Google, post-2000
- To avoid confusion or difficulty in reading: de-energize, intra-index, re-mark, re-sign
- If the prefix is for a term that already has hyphens or spaces: un-Google-like, non-twentieth-century
- To be consistent within a document: pre-processing, post-processing
The non prefix
The non prefix follows the same guidelines, but because it can easily form words that are hard to parse, it's often hyphenated. Use your best judgment, taking into account consistency within your documentation. The following recommendations show contrasting usages that you can use as examples.
Recommended: noncurrent, nonempty, noninteractive, nonpublic
Recommended: non-existence, non-integer, non-key, non-managed, non-negative
When using non as a prefix, add a hyphen before hyphenated compound words.
Recommended: non-KSA-based,
non-self-sustaining
A compound is a term that combines more than one word. Compounds can
be closed as one word with no spaces, open with spaces between
words, or hyphenated. In general, write compound nouns in their closed (one-word, unhyphenated)
form. If you see that
Merriam-Webster.com uses the
two-word or hyphenated form, but you see that the closed form is the
predominant convention in your context or trending in that direction (as
compounds often do), then use the closed form. Recommended: webpage Recommended: hostname Recommended: tradeoff Recommended: workaround Our word list includes exceptions for
well-established terms that commonly use a hyphen or a space, such as
multi-region and style sheet. In some cases, we note that noun,
verb, and adjective versions of a word are treated differently. When the components of a unit of measurement are multiplied by each other,
hyphenate them. Recommended: 5 vCPU-hours Recommended: 40 person-hours If needed for clarity, hyphenate compound modifiers that come before a noun.
This guideline can be subjective. However, except as noted in
this section, it's almost never wrong to hyphenate a compound before a
noun to ensure clarity. Recommended: A well-designed app Recommended: Android-specific
techniques Use a hyphen after more or most if you need to clarify what
those words modify. Recommended: The most common scenario Recommended: Edge locations with
more-reliable internet links In general, avoid writing compound modifiers that have more than two words.
Instead, move some words after the noun. If you must use this type of
compound, then use a hyphen between each word as needed for clarity.
Recommended: test cases
that are specific to the 2023 edition Recommended:
cross-data-center replication Not recommended:
edition-2023-specific test cases Don't hyphenate adverbs that end in -ly except when needed for clarity. Recommended: Publicly available
implementations Not recommended: Publicly-available
implementations Don't use hyphens in compounds that are conventionally not hyphenated. Follow the
guidance in the word list
or check the convention in the documentation that you're working with. Recommended: A managed
instance group (MIG) Recommended: A machine
learning model When a number and unit of measurement combine to modify a noun, don't hyphenate unless
the hyphen is needed for clarity. Recommended:
In general, you don't need to add a hyphen to a compound that follows a verb. Recommended: The app is well
designed. Recommended: The logs are written
in real time. Recommended: The product supports
high availability. Recommended: The app uses techniques
that are Android specific. Recommended: Customers can use
the utility as is. Recommended: Get profile information
for the currently authorized user. Some compound terms are always hyphenated, even if they follow a verb. To
check, look the term up in the word list. If it isn't in the
list, check the Merriam-Webster dictionary.
As always, follow the convention in the documentation that you're working with. Recommended: You can deploy the app
on-premises. Recommended: The docs describe how
to create an add-on. Recommended: The utility works
with apps that are cloud-based and cloud-adjacent. Recommended: This page is
customer-facing. Recommended: The app is designed
to be user-friendly. Recommended: The goal is to produce
an experience that's game-like. Use a hyphen, not an en dash ( Recommended: 8-20 files Recommended: 5-10 minutes Recommended: from 8 to 20 files Not recommended: from 8-20 files Never place a space on either side of a hyphen except when using a
suspended hyphen, in which case you can leave a space after
(but not before) the hyphen. When two or more compound modifiers have a common base, you can keep the
hyphens but leave out the base for all except the last modifier. In the
following examples, the base is hour. Recommended: You can set up the system to
scan for new files at one- or two-hour intervals. Recommended: You can set up the system to
scan for new files at one-, two-, or three-hour intervals.Compounds
Compound nouns
Exceptions
Compound modifiers before a noun
Exceptions
200 GB disk (200 GB disk)Compound terms after a verb
Exceptions
Range of numbers
–),
to indicate a range of numbers. If a hyphen introduces ambiguity, use words such as
from, to, and through for clarity. Don't mix hyphens with words.
For information about how to represent a range of numbers that includes units, see
Ranges of numbers with units.Spaces around hyphens
Suspended hyphens