Used and loved by millions
Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.

Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com
at what day
Grammar usage guide and real-world examplesUSAGE SUMMARY
The phrase "at what day" is not correct in standard written English.
It is typically used when inquiring about a specific day related to an event or occurrence, but the more common phrasing would be "on what day." Example: "At what day is the meeting scheduled to take place?"
⚠ May contain grammatical issues
News & Media
Wiki
Science
Alternative expressions(20)
what is the sacrifice
at what rate
at what dose
at what point
at what premium
at what investment
at what altitude
at what Everything
at what margin
at what fare
at what hour
at what stage
at what service
what are the repercussions
date of the event
at what size
at what economic
when did it happen
what are the implications
at what frequency
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Human-verified examples from authoritative sources
Exact Expressions
6 human-written examples
"You call those seven people and go through their food history, what restaurants they ate at, what day did you eat there, where did you buy that milk or ground beef," said Downes.
News & Media
Don't look at what day it was.
News & Media
In question five, Miller states: PIP will use the biopsycosocial model of disability to look at what day to day activities each individual can do and what they need support with.
News & Media
Is it the intention that people with these conditions - and other fluctuating conditions, such as mental illness - might lose eligibility for PIP? PIP will use the biopsycosocial model of disability to look at what day to day activities each individual can do and what they need support with.
News & Media
At what day of the week should they buy?" adds Kaul.
News & Media
At what day?
Wiki
Human-verified similar examples from authoritative sources
Similar Expressions
52 human-written examples
It's nice to know what time of day I'm at my busiest, what day of the week, what buzzwords appear most in my email chains, and who is the unfortunate soul who receives most of my email communications.
News & Media
How many pictures are taken at a place, at what time, on what day: That all helps us decide how important a location is".
News & Media
As I remember, the teachers were sometimes at a loss for what day it was, too.
News & Media
Create an outline for your posting plan that indicates what day, at what time and exactly what content will go out.
News & Media
Nobody even knew where it was going to be, exactly, or on what day, or at what time.
News & Media
Expert writing Tips
Best practice
When asking about a specific day, use the preposition "on" instead of "at". For example, use "on what day" is the meeting scheduled?
Common error
Avoid using "at" when referring to specific days; "at" is generally used for times (e.g., "at 3 PM") or locations. Always use "on" when specifying a day of the week or date.
Source & Trust
82%
Authority and reliability
2.8/5
Expert rating
Real-world application tested
Linguistic Context
The phrase "at what day" functions as an interrogative phrase, attempting to inquire about a specific day. However, it is grammatically incorrect according to Ludwig AI, which recommends using "on what day" instead. The examples in Ludwig show varied contexts where the phrase is used, despite its grammatical issues.
Frequent in
News & Media
57%
Wiki
14%
Science
29%
Less common in
Formal & Business
0%
Academia
0%
Encyclopedias
0%
Ludwig's WRAP-UP
The phrase "at what day" is used to inquire about a specific day, but it's grammatically incorrect; standard English dictates using "on what day" instead. Despite its prevalence in various sources, including news and media, as shown by Ludwig, the phrase does not conform to grammatical standards. Ludwig AI identifies it as incorrect, so using "on what day" or alternatives like "which day" ensures clarity and grammatical accuracy. The frequency of the expression is uncommon, and while its purpose is clear, adhering to correct grammar enhances communication.
More alternative expressions(6)
Phrases that express similar concepts, ordered by semantic similarity:
on what day
Replaces "at" with "on" to conform to standard English preposition usage when referring to days.
which day
Uses "which" to specify a particular day, offering a more direct and grammatically sound question.
what day of the week
Clarifies the inquiry to specifically ask about the day of the week, adding context for better understanding.
on what date
Substitutes "day" with "date" to ask for the specific calendar date, providing a clearer request.
the day on which
Restructures the sentence to use a relative clause, making it grammatically correct and more formal.
date of the event
Focuses on the event by directly asking for its date, changing the sentence structure significantly.
when did it happen
Asks about the timing of an event, using a simple and direct question format.
time of the event
Focuses on the time of the event, shifting the focus from the day to the specific time.
schedule date
Asks directly for the scheduled date, implying a need to know when something is planned.
exact day
Emphasizes the need for precision by asking for the exact day, adding a sense of urgency or importance.
FAQs
What is the correct way to ask about a specific day?
The correct way to ask about a specific day is to use the preposition "on" rather than "at". For instance, say "on what day is the event scheduled?"
Is it grammatically correct to use "at what day" in a sentence?
No, it is not grammatically correct. Standard English uses "on" when referring to days. Therefore, the correct phrasing is "on what day".
What can I say instead of "at what day" to ask about a day of the week?
You can use alternatives such as "what day of the week", or simply "which day".
What is the difference between "at what day" and "on what day"?
"At what day" is grammatically incorrect. The correct phrase is "on what day", which is the standard way to inquire about a specific day.
Editing plus AI, all in one place.
Stop switching between tools. Your AI writing partner for everything—polishing proposals, crafting emails, finding the right tone.
Table of contents
Usage summary
Human-verified examples
Expert writing tips
Linguistic context
Ludwig's wrap-up
Alternative expressions
FAQs
Source & Trust
82%
Authority and reliability
2.8/5
Expert rating
Real-world application tested