Signup or Sign Up: Which One Is Correct?

Signup or sign up? Or sign-up, with a hyphen? All three forms appear on websites, apps, and forms, and they look interchangeable, but they are not. One form is the verb. One form is the noun and adjective in dictionaries. One form is common in tech writing, but it is not the dictionary form. Using the wrong form is a small mistake, but on a website it looks unprofessional, because visitors see it on buttons and headings. This guide explains each form, the plural, and how to use them on websites and forms.

Quick Answer

Quick Answer: Sign up, in two words, is the verb, meaning to register, as in sign up for the course. Sign-up, with a hyphen, is the noun and adjective in dictionaries, as in the sign-up form, or the sign-up is open. Signup, in one word, is common in tech and UX writing, as in a signup page, but it is not the dictionary noun form. For careful writing, use sign up for the action, and sign-up for the thing. Use signup only when a tech style guide asks for it.

Meaning and Definition

Sign up, as a verb phrase, means to register, join, or enrol, as in sign up for a newsletter. It describes an action, done by a person. Sign-up, as a noun, means the act of registering, or the registration itself, as in the sign-up takes two minutes. Sign-up, as an adjective, comes before a noun, as in a sign-up form, a sign-up page, or a sign-up bonus. Signup, as a noun, means the same as sign-up in tech writing, as in the signup is open, but dictionaries list the hyphenated form, sign-up, for the noun and adjective. The meaning is the same across forms, but the job, verb or noun, decides the spelling.

Comparison Table

Form	Part of Speech	Example
Sign up	Verb	Please sign up for the course.
Sign-up	Noun	The sign-up takes two minutes.
Sign-up	Adjective	Complete the sign-up form.
Signup	Noun, tech/UX	The signup page is live.
Sign up	Verb	I want to sign up today.

Signups or Sign-Ups?

The plural follows the same pattern. Sign-ups, with a hyphen, is the dictionary plural of the noun, as in we had fifty sign-ups this week. Signups, in one word, is the plural in tech and UX writing, as in we had fifty signups this week. The verb has no plural form, because verbs do not take a plural s in this way. You do not write signs up for a plural, you write they sign up, with the verb unchanged. For careful writing, use sign-ups, with a hyphen, for the plural noun. For tech writing, signups, in one word, is acceptable, if the style guide uses it consistently.

Sign Up vs Log In vs Sign In

Sign up means to register for the first time, creating a new account. Log in and sign in both mean to enter an existing account, with a username and password. Sign in is the common verb phrase for returning users, as in sign in to your account. Log in is a close synonym, as in log in to your account, and it follows the same pattern: log in is the verb, log-in is the noun and adjective. The mistake to avoid is using sign up for returning users. If a person already has an account, they sign in or log in, they do not sign up again. If a person is new, they sign up first, then they sign in later.

Using Signup on Websites and Forms

On websites and forms, the form matters most, because visitors see it. Button labels usually use the verb, as in Sign up, in two words, because the button asks the visitor to act. Headings for the form itself often use the noun, as in Sign-up, with a hyphen, because the heading names the thing. Tech sites often use Signup, in one word, for page titles and links, as in Signup, because tech style guides prefer the closed form. Whichever form a site chooses for the noun, it should use it consistently, on every page, button, and heading. Mixing sign-up, signup, and sign up for the same thing looks careless, even when each form is correct on its own.

Examples in Sentences

• Please sign up for the newsletter.
• The sign-up takes only two minutes.
• Complete the sign-up form before Friday.
• The signup page is live on the website.
• I want to sign up for the course today.
• We had fifty sign-ups this week.

Common Mistakes

• Wrong: I want to signup. Correct: I want to sign up, because signup is not the verb, sign up is.
• Wrong: Complete the sign up form, as an adjective. Correct: Complete the sign-up form, because the adjective before a noun is hyphenated in dictionary form.
• Wrong: The signup is open, in formal writing, as the dictionary noun. Correct: The sign-up is open, because the dictionary noun is hyphenated.
• Wrong: Sign up again, for a returning user. Correct: Sign in again, for a returning user, because sign up means register for the first time.

The most common error is using the noun form as a verb, or the verb form as a noun or adjective. Checking the job, action or thing, catches the mistake.

Tips to Remember

Ask: Is it an action or a thing? An action, to register, means sign up, in two words. A thing, the registration or the form, means sign-up, with a hyphen, in dictionary form. A simple test is to try the word register. If you can replace it with register, you need the verb, sign up. If you can replace it with registration, you need the noun, sign-up. Signup, in one word, is a tech variant for the noun, acceptable only when a tech style guide uses it. Other tricky spellings also become easier when you check the job of the word, action or thing, instead of guessing from the sound.

Kickoff or Kick-Off follows the same action-or-thing pattern.

Frequently Asked Questions About Signup or Sign Up

Conclusion

Sign up, in two words, is the verb. Sign-up, with a hyphen, is the noun and adjective in dictionaries. Signup, in one word, is common in tech and UX writing for the noun, but it is not the dictionary form. Check whether you mean an action or a thing, and the right form will follow.