Prepositions in English can sometimes be complicated to use. Should you say “In the same day” or “On the same day”? And what about “At the same day”? This article will answer any questions you could have about how to use this expression in the correct way.
Both “In the same day” and “On the same day” are correct to use, for slightly different situations. “In” is used for a day as a timeframe, and “On” is used for a day as a date. Rather, you shouldn’t use “At the same day” because “At” is not used for dates or timeframe.
Both “In the same day” and “On the same day” can be used, with slightly differing contexts. “On the same day” should be used when talking about a specific day of the week or date.
On the other hand, “In the same day” is used when referring to a day as a time frame in which something took place.
In this context, “In the same day” is similar to saying “In an hour” or “In a year”.
“At” is the wrong preposition to use when talking about a specific day or date, because “At” is used instead for time, rather than dates or time frames. You’d use “at” when talking about a specific hour of the day.
According to information compiled by the Google Ngram Viewer, “On the same day” has been vastly more utilized than “In the same day” and “At the same day” for decades.
The data showcases the fact that “On the same day” has been popular in its use since the year 1900 at least, while “At the same day” and “In the same day” have remained similarly unpopular since.
“In the same day” has always been more popular than “At the same day”, most likely because of the fact that the latter is a grammatically incorrect construction.
However, it’s worth pointing out that in spite of the fact that it remains immensely more popular in use than the other two expressions, “On the same way” has been steadily decreasing in popularity for decades.
Meanwhile, “At the same day” has remained stable in how miniscule its number of uses is, but “In the same day” has been slowly increasing in use since the early 1990s.
It’d yet take a few more decades for “In the same day” to even come close to surpassing “On the same day” in use, with the former increasing in use and the latter decreasing.
That being said, it’s still a possibility that might happen one day.
No, it’s never correct to use “At the same day”. The preposition “At” should be used with specific times, or locations, but not dates or days.
An example of how to properly use the preposition “At” would be the sentence “We will meet at 5:00 p.m”. In this sentence, “At” is being used to signal a specific time.
“In the same day” should be used when talking about a specific day as a timeframe or a period of time.
In this context, you’re not talking about a “Day” as in a week day, or a date, but you’re instead referring to a “Day” as a space in which time passes.
Here are some example sentences if you’re confused about what this means:
- We went to three bars in three hours.
- I decided to do all of my work in the same day.
- They were about to bulldoze five whole buildings in the same day.
- We weren’t sure how we were going to read all the documents in the same day.
- I was making sure that all of the pastry would be baked in the same day.
- In the same day that I graduated, my laundry machine broke.
- She made sure that I did all of my housework in the same day.
- He was certain he could eat all five meals in the same day.
- In the same day I wrote all of the remaining essays.
- They finished all six short films in the same day.
“On the same day” should be used when talking about a “Day” as a calendar date or moment in time.
“On” is the correct preposition to use whenever you’re talking about an individual date where it doesn’t matter how much time it spans.
Some examples of such dates would be holidays, or week days, or even calendar dates.
Here are some example sentences to clarify whatever remaining questions you could have:
- On the same day that I got married, my father passed away.
- My daughter was born on the same day that my best friend’s son was born.
- The film’s sequel released on the same day as the previous movie in the franchise.
- On the same day as the national blackout, I finally finished my dissertation.
- I read the book on the same day as you did.
- On the same day I returned home, and so did he.
- I ventured forth on the same day as I had been born.
- I watched the movie on the same day as I had last year.
- She got married on the same day as her mom.
- I decided to let go on the same day as she did.
They can often be interchangeable, but are not necessarily so. A sentence that uses the “In” preposition might also be able to use the “On” preposition, but the reverse might not be the case.
This is because “In” refers to a specific period of time, while “On” just refers to a specific date.
So they can often overlap, but “In” is about the time passed in the day, while “On” refers to the day itself.
So a sentence that has two events happen on the same day might be described as “In the same day” if the fact that both occurred in the same day is notable.
However, this sentence might also be described as “On the same day”:
The difference between “On the same day” and “On the same date” is that “On the same day” can refer to any particular day of the week, while “On the same date” means a specific day associated with a specific number of the month and year.
So if someone asks what the day is, you could answer “Monday” or “Tuesday”, but if someone asks what the date is, you could answer “January 18th” or “November 2nd”.
Here are some more detailed examples to clarify what is meant by this:
- I went to the movies on the same day as she did, by coincidence.
- We ended up getting married on the same date.
- I gave birth on the same date as my best friend.
- On the same day I went to the cleaner’s and he came back home.
Yes, “Within the same day” is correct. It’s an expression freely interchangeable with “In the same day”.
The “In” preposition refers to, in this context, something happening in a specific time span. “Within” is a more extensive way of communicating that idea.
This means that “In the same day” and “Within the same day” are interchangeable in all contexts.
Martin holds a Master’s degree in Finance and International Business. He has six years of experience in professional communication with clients, executives, and colleagues. Furthermore, he has teaching experience from Aarhus University. Martin has been featured as an expert in communication and teaching on Forbes and Shopify. Read more about Martin here.