Someday vs some day: What’s the difference?

Someday vs some day?

The word someday is used to describe an event or series of events to occur at an indefinite future time. The phrase some day is used to refer to an unplanned event taking place on a probable, specific day.

For example, one might say,

Someday I will write for the Wallstreet Journal. Some day this week, I will find time to practice writing.”

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What’s the difference between someday and some day?

Understanding the difference between someday and some day can appear minutia in terms of grammar lessons because it’s an example of how native English-language speakers take their connotations for granted. However, it’s crucial to understand the difference between someday and some day to convey information to your audience as clearly as possible.

An easy way to remember the difference between someday and some day is to ask yourself:

  • How far in the indefinite future will the event take place?
  • How long will the event occur?

If you’re referring to a future event that will occur on an unspecified, single day, then you would use the phrase some day. If you’re referring to an occasion, or series of events at a distant, indefinite time, then using the word someday is correct.

Another tip to keep in mind is how the word someday only refers to future tense statements. The word phrase some day can refer to a time in the past or future tense.

In the event you’re deciding on how to best use someday or some day for essay and proposal writing, it’s best to avoid using either one. Unless you’re using the pronoun some to provide specific examples, the words some and someday infer uncertainty and can easily produce unclear sentences altogether.

Incorrect usage in speech

Distinguishing the difference between the word someday and the phrase some day is difficult for grammar students because people often use them interchangeably in speech. It’s not uncommon to hear somebody say,

Someday soon, we should meet up and have coffee,”


Someday, it will happen.”

Both examples of speech are grammatically correct, but they’re technically inaccurate. The first example is used in the wrong context because someday infers an undetermined date in the distant future. Following someday with the word soon creates a contradicting tautological statement by conveying the same information twice but in different words. The second example is another common utterance that represents another tautology.

someday vs some day

Incorrect usage in writing

Online news media columns even make the mistake of using the two sayings interchangeably, such as the Star Tribune’s headline,

“A recession is coming, some day. Are you prepared?”

The headline’s use of some day is incorrect because the article doesn’t convey a time or place in the near future that a recession will occur. Furthermore, the use of some day infers that an event will take place within 24 hours, or one day. A recession is a period where an economy experiences a decline in financial prosperity or stability. The shortest recession to take place in United States history occurred over six months in 1812, so it’s inaccurate to infer how a recession would occur and end within one specific day.

Audiences typically understand the intended conclusion when someday or some day are substituted for one another. Nevertheless, the incorrect usage of someday and some day can create confusion, or mild panic, for communicating important messages.

What does someday mean?

The word someday is an adverb used to describe an event or moment that will occur in the future, or at a later time. The future date of someday is located in the indefinite future, which means the event can take place in the near or extended future.

Is someday a compound word?

Someday is a compound word consisting of the adjective “some” and the noun “day.”

How do you use someday in a sentence?

Someday is traditionally used in the following examples:

  • Someday, I’ll return to the Trevi Fountain in Rome.”
  • “You’re going to be a great leader someday.”
  • “Let’s revisit this idea someday next year.”
  • Someday, I’m going to climb a giant, magical beanstalk into the clouds, walk into another dimension, and fight an evil giant with a sword.”

As shown in the last example, the word someday is also used as a figure of speech to describe a hopeful, improbable moment where the speaker and audience are aware the event will never occur.

Synonyms of someday

  • Eventually
  • Sometime
  • Yet
  • Ultimately
  • Sooner or later

Antonyms of someday

  • Immediately
  • Pronto
  • Promptly
  • Right now
  • Right away
  • Straight away
  • Never
  • Nevermore

Etymology of someday

According to the Online Etymology Dictionary, the word someday was first used as one word in 1768 and derived from the phrase some day stemming from the late 14th Century. Until the words some day became someday, they were capable of representing the same meaning. 

What does some day mean?

The phrase some day is used to describe an unspecified, but specific day where an event will take place within a 24-hours. The phrase infers the event occurs scheduled in the more-near future than one that is further away.  Some day consists of the adjective, some, and the noun, day.

When used as an adjective, the word some is defined as an undetermined and indefinite-quantity that describes a person, place, or thing. In its adjective form, the word some shares its definition with its adverb and pronoun forms, but only under the context of using “some” in a phrase like “some day.”

The complexity of using the word some is why distinguishing someday from some day is confusing to English speakers. As a pronoun, some is used to describe an indefinite amount of something. As an adverb, however, some is synonymous with the words “about” and “somewhat,” which are often used to vaguely describe a non-approximate, or rounded quantity of time, people, things, etc.

Some examples of “some” that are consistent with the phrase some day:

  • Some (adj.): “Can I have some candy?”
  • Some (pronoun): “I bought candy every day and then some.”
  • Some (adverb): “There are 30-some days left until we have to meet up.”

It’s important to not confuse the phrase some day with some’s other adjective form. As a figure of speech, some can be used to describe something as odd or eccentric. It’s not uncommon to hear people say, “Some day this is, right?” When people say this, they’re often commiserating how strange their day has been with another person who is sharing the same experience.


How do you use some day in a sentence?

Examples of how to use the phrase some day include:

  • “Let’s meet up on some day in November for Thanksgiving.”
  • “She’s supposed to visit her mom on some day next week.”
  • “There’s some day or time we’re expected to pay taxes, right?”
  • Someday, I’ll be a millionaire, but until then, I’ll go to work until I quit on some day in March.”

Similar phrases to some day

  • Some time
  • One day
  • A day

Related FAQ: some day vs. someday

What is an adverb?

An adverb clarifies another adverb, adjective, or verb that answers the question of how, when, where, how much, and how often. Adverbs are easily recognizable when they end with “-ly,” such as dearly, proudly, or wholly. Other examples include above, today, quite, and often.

What is a tautology?

A tautology is a statement using two or more words that mean the same thing, where a single word is sufficient to convey the writer’s message. Tautological statements often include:

  • “…my own…”
  • “…conducting research…”
  • “…new innovations…”

Test Yourself!

Choose the correct version of someday or some day

  1. Would you like to schedule your appointment for ___________ next month?
    1. Someday
    1. Some day
  2. ___________ you will learn the difference between someday and some day.
    1. Some day
    1. Someday
  3. ___________ next week, we can go to the movies and eat popcorn.
    1. Someday
    1. Some day
  4. Would you like to go on a date ___________?
    1. Some day
    1. Someday
  5. ___________ are happy and ___________ we can be happy all the time.
    1. Someday, some days
    1. Some days, someday


  1. Some day
  2. Someday
  3. Some day
  4. Someday
  5. Some days, someday


  1. Adjective or Adverb.” Effective Writing Practices Tutorial, Northern Illinois University, 2019.
  2. A recession is coming, some day. Are you prepared?” Chris Farrell. Star Tribune, Star Tribune Media Company, LLC, Sept. 3, 2019.
  3. Appendix A: The Development and Role of the National Bureau of Economic Research’s Business Cycle Chronologies.” Geoffrey H. Moore, Victor Zarnowitz. The American Business Cycle: Continuity and Change, National Bureau of Economic Research, University of Chicago Press, 1986.
  4. Improving Sentence Clarity.” Purdue Online Writing Lab, Purdue University, 2019.
  5. Tautology.” Merriam-Webster Dictionary, Merriam-Webster, Inc., 2019.
  6. Someday.” Lexico Dictionary, Oxford University Press, 2019.
  7. Someday.” Merriam-Webster Dictionary, Merriam-Webster, Inc., 2019.
  8. Someday.” Merriam-Webster Thesaurus, Merriam-Webster, Inc., 2019.
  9. Someday.” Online Etymology Dictionary, Douglas Harper, 2019.

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