Goodnight or Good Night: Which Is Correct?
Goodnight or good night? Both forms appear in messages, books, and greetings, and both are understood, but they are not used in exactly the same way. The two-word form is the standard farewell and the standard noun phrase. The one-word form is an informal farewell variant, and it is also the form used as a modifier before a noun. This guide gives one consistent rule, with clear examples, so you never have to guess.
Quick Answer
Quick Answer: Good night, in two words, is the standard form for a farewell, as in Good night, see you tomorrow, and for describing a night, as in have a good night. Goodnight, in one word, is an informal variant of the farewell, common in texts and casual writing, and it is the form used as a modifier before a noun, as in a goodnight kiss, or in the phrase say goodnight. For a standard, careful farewell, use good night, in two words. For a modifier, use goodnight, in one word.
Good Night (Two Words): Farewell and Describing the Night
Good night, in two words, is the standard farewell when parting at night or before sleep. For example: Good night, Mum, see you in the morning. It is also a noun phrase, where good describes night, as in I hope you have a good night. In this noun phrase use, the two-word form is the correct one, not the one-word form. For example: She had a good night’s sleep, with good night’s showing possession, is the grammatically standard form. Dictionaries list good night as the standard entry, with goodnight as a variant, which is why the two-word form is the safe choice in formal and careful writing.
Goodnight (One Word): Noun/Adjective and Informal Variant
Goodnight, in one word, has two main uses. First, as an informal farewell variant, common in texts, messages, and casual writing, as in Goodnight, see you tomorrow. It means the same as good night in this use, but it is less formal, so it is best avoided in a formal letter or a business email. Second, as a modifier before a noun, where the one-word form is the standard choice. Examples are a goodnight kiss, a goodnight story, and the phrase say goodnight, where goodnight acts as a noun. In these modifier uses, do not split it into two words. A good night kiss, with two words, looks wrong as a modifier, because the modifier must be one closed compound word.
Comparison Table
| Form | Use | Example |
|---|---|---|
| Good night | Standard farewell | Good night, see you tomorrow. |
| Good night | Describing a night | Have a good night. |
| Goodnight | Informal farewell | Goodnight, see you tomorrow. |
| Goodnight | Modifier before a noun | A goodnight kiss. |
Goodnight or Good Night in Texts and Messages
In texts and messages, both forms appear, and both will be understood. Good night, in two words, is still the standard choice, even in a text, and it never looks wrong. Goodnight, in one word, is very common in texts, because it is shorter and feels casual, like a single greeting. If you are texting a friend, either form is fine. If you are writing a formal message, such as a work email or a condolence note, use good night, in two words. The rule does not change in texts. It only feels looser, because casual writing allows the informal variant more often.
American vs British Usage
In both American and British English, good night, in two words, is the standard farewell and noun phrase, and goodnight, in one word, is the informal variant and the modifier form. There is no large regional split here. American dictionaries and British dictionaries both list good night as the standard entry, with goodnight as a variant. British writing may show goodnight slightly more often in casual messages, and American writing may show it in song titles and informal greetings, but the careful rule is the same in both regions. Use two words for the standard farewell, one word for the modifier, and you will be right in both.
Examples in Sentences
- Good night, Dad, sleep well.
- I hope you have a good night.
- She gave him a goodnight kiss before bed.
- They said goodnight and went upstairs.
- We had a good night’s sleep after the long walk.
- Goodnight, everyone, see you in the morning.
- He read her a goodnight story.
Common Mistakes
- Wrong: A good night kiss, as a modifier. Correct: A goodnight kiss, as a modifier. Note: modifiers use the one-word form.
- Wrong: Have a goodnight, as a noun phrase describing the night. Correct: Have a good night, as a noun phrase. Note: describing a night uses two words.
- Wrong: Goodnight is always wrong. Correct: Goodnight is an accepted informal farewell variant, and it is the standard modifier form, so it is not always wrong.
- Wrong: Good night story, as a modifier. Correct: Goodnight story, as a modifier. Note: the same modifier rule applies.
The most common error is using one form for every use. The fix is to check the job. Farewell and describing a night mean two words. Modifier before a noun means one word.
Tips to Remember
Ask: Am I describing a night, or modifying a noun? Describing a night, as in have a good night, means two words. Modifying a noun, as in a goodnight kiss, means one word. For a farewell, the standard choice is two words, good night, and the informal choice is one word, goodnight. A simple memory aid is: two words for the night itself, one word for the thing before a noun. Other tricky spellings also become easier when you check the job of the word, instead of guessing from how it sounds.
Frequently Asked Questions About Goodnight or Good Night
Both are correct, in different uses. Good night, in two words, is the standard farewell and noun phrase. Goodnight, in one word, is an informal farewell variant and the modifier form.
Either will be understood in a text. Good night is the standard choice, and goodnight is the casual, shorter choice. For a formal message, use good night.
One word. As a modifier before a noun, goodnight is a closed compound word, as in a goodnight kiss.
Two words. Have a good night describes a night, so it uses the noun phrase form, good night.
Both regions use both forms, with the same rule. Good night is standard in both, and goodnight is the informal variant and modifier in both.
Good night’s sleep, with two words and an apostrophe s, is the standard form, because it is the noun phrase good night showing possession.
Conclusion
Good night, in two words, is the standard farewell and the form for describing a night. Goodnight, in one word, is the informal farewell variant and the form for a modifier before a noun. Check the job, farewell or description means two words, modifier means one word, and the choice will be consistent every time.
