Hyphens

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):

  1. 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.
  2. The word list in this style guide.
  3. The Merriam-Webster dictionary.

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

Compound modifiers before a noun

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

Exceptions

  • 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

Compound terms after a verb

In general, don't hyphenate compounds that follow the 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.

Exceptions

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.

Range of numbers

Use a hyphen, not an en dash (–), 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.

Recommended: 8-20 files

Recommended: 5-10 minutes

Recommended: from 8 to 20 files

Not recommended: from 8-20 files

Spaces around hyphens

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.

Suspended hyphens

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.