Have you ever paused while writing a sentence and wondered: is it “someday” or “some day”? You’re not alone.
This is one of the most common English writing confusions, especially for learners, bloggers, students, and even native speakers.
Both forms look almost the same. Both sound exactly the same when spoken. Yet, they do not always mean the same thing.
People search for “someday or some day” because they want a quick, clear answer without grammar jargon.
They want to know which spelling is correct, when to use each one, and whether British or American English changes the rule. This confusion often shows up in emails, social media posts, essays, and professional writing.
This guide solves that problem completely. You’ll get a simple explanation, real-life examples, spelling history, and usage advice based on your audience.
By the end, you’ll know exactly when to use someday and when some day—with confidence and clarity.
Quick Answer
Someday (one word) means at an unknown time in the future.
Some day (two words) means a specific day, though not named.
Examples:
- I hope to travel the world someday.
- Let’s meet some day next week.
Simple rule:
If you can replace it with “in the future”, use someday.
If you can replace it with “a certain day”, use some day.
The Origin of Someday or Some Day
The phrase some day came first in English history. In Old and Middle English, words were often written separately. Over time, commonly used word pairs merged into single words. This process also gave us words like today, tonight, and already.
Someday evolved as people began using the phrase to talk about a vague future time. As usage increased, the two words slowly joined into one.
That’s why both forms exist today. English kept the older two-word form (some day) and also accepted the newer combined form (someday). The spelling difference exists because the meaning slightly changed over time.
British English vs American English Spelling
Good news: British and American English follow the same rule for someday and some day. There is no spelling conflict like color vs colour.
The difference is meaning-based, not region-based.
Comparison Table
| Form | Meaning | US English | UK English |
| someday | Unclear future time | ✅ Yes | ✅ Yes |
| some day | A particular day (unspecified) | ✅ Yes | ✅ Yes |
Key point:
Both spellings are correct in both British and American English.
Which Spelling Should You Use?
Your choice depends on meaning and audience clarity, not location.
Use someday when:
- Writing about dreams or long-term goals
- Talking about hopes or future plans
- Writing creatively or casually
Example:
- She believes she will become a doctor someday.
Use some day when:
- Referring to an actual day
- Making plans or schedules
- Writing formally or precisely
Example:
- We should discuss this some day after the meeting.
Audience-based advice:
- US audience: Follow meaning-based rule
- UK/Commonwealth audience: Same rule applies
- Global audience: Use someday for future ideas, some day for specific timing
Common Mistakes with Someday or Some Day
Many writers mix these forms without thinking about meaning.
Mistake 1: Using some day for future dreams
❌ I will be rich some day.
✅ I will be rich someday.
Mistake 2: Using someday for a planned date
❌ Let’s finish the report someday next week.
✅ Let’s finish the report some day next week.
Mistake 3: Assuming British vs American difference
❌ Thinking spelling depends on country
✅ It depends only on meaning
Someday or Some Day in Everyday Examples
Emails
- I hope we can work together someday.
- Let’s schedule the call some day in March.
News Writing
- The project may be completed someday, officials say.
- The law will be reviewed some day during the session.
Social Media
- Someday I’ll buy my dream car.
- Some day this post will make sense.
Formal Writing
- The theory may be proven someday.
- The committee will decide some day this year.
Someday or Some Day – Google Trends & Usage Data
Search data shows that “someday” is used more often worldwide than “some day.” This is because people talk more about future hopes than specific unnamed dates.
Usage by context:
- Motivation & quotes: someday (very common)
- Planning & scheduling: some day
- Casual writing: someday
- Formal writing: both, depending on meaning
Keyword Comparison Table
| Variation | Frequency | Common Use Case |
| someday | High | Dreams, future plans |
| some day | Medium | Scheduling, planning |
FAQs
1. Is “someday” one word or two?
It can be both. The meaning decides the spelling.
2. Is “some day” grammatically correct?
Yes. It refers to a specific but unnamed day.
3. Do Americans and British use it differently?
No. Both follow the same meaning-based rule.
4. Can I use “someday” in formal writing?
Yes, when talking about an unclear future time.
5. Which form is more common?
Someday is more common in general usage.
6. Is “someday” informal?
No. It is acceptable in both formal and informal writing.
7. How can I remember the difference?
If it means in the future, use someday.
If it means a particular day, use some day.
Conclusion
The confusion between someday or some day is common, but the solution is simple. Both spellings are correct English. The difference is not about British or American rules—it’s about meaning.
Use someday when talking about hopes, dreams, or an unknown future time. Use some day when referring to an actual day, even if you don’t know exactly which one.
This small difference can make your writing clearer, more professional, and easier to understand.
For bloggers, students, and professionals, mastering this distinction helps avoid common grammar mistakes and builds confidence.
When in doubt, test the sentence. If “in the future” fits, choose someday. If “a certain day” fits, choose some day.
Clear writing starts with small choices—and this is one you now fully understand.
