In modern professional life, it’s not enough to be great at your job. You also need to be a skilled business communicator. It means knowing the meaning of acronyms like COB and EOD and how to use them.
It’s especially crucial if you are a new entrant into the remote workforce. How often do you receive an email asking you to submit an assignment by COB or EOD?
These acronyms and others like them make lengthy emails clearer and heighten professionalism, but not everyone uses them the same way. And it doesn’t help that some people use both interchangeably.
As a result, they can leave the recipient confused and anxious. Even worse, miscommunication can lead to missed deadlines and cause a negative business impact.
Below, you will learn what these terms mean, how to use them correctly when communicating with coworkers, and examples to follow.
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Generally, COB means “close of business.” It refers to the end of the business day, defined by the time businesses traditionally close. In the United States, this is typically 5 PM Eastern Standard Time (EST).
Although it is a semantic difference, COB can also refer to the time stock markets close in New York City, which is also 5 PM EST. That’s why COB is a common acronym among business professionals.
In this context, when an employer uses COB in writing, and you are in a different time zone, they are referring specifically to US hours rather than COB in your local time zone.
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EOD is a term that stands for “end of (the) day.” Like COB, business professionals also use it to refer to the end of the business day, which also means 5 PM in the US.
The term was first used in the 1800s. It started gaining widespread usage in the 1980s because of the rising popularity of computers.
In practical terms, when professional organizations use EOD in their communication, it’s done to set a deadline for a task. When you see an email that says to complete an assignment at EOD, you should have it ready by 5 PM.
However, the exact hour is relative to the country. If you’re in Mexico, where offices close by 6 PM, a request to complete a task by EOD means the deadline is 6 PM.
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Professionals commonly use EOD and COB interchangeably due to their similarities. In some organizations, they mean the same thing.
Generally speaking, there are two key differences between COB and EOD. The first difference is location-based.
If an employer wants a task completed by COB and you’re both in the same time zone, it means the deadline is at the end of the local business hours.
However, if you are in separate time zones, EOD usually means by the end of the business day in the sender’s time zone.
The second key difference is time-based. COB refers specifically to New York stock market trading hours – 5 PM EST. Even if you are in a different time zone, COB is pegged to the end of regular trading hours.
On the other hand, EOD can also refer to any time after work. When used like this, it means the task will be completed sometime after the close of normal business hours and before the start of a new day.
Knowing this, we are left with one question: what is considered a business day?
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Generally speaking, business days are working hours outside of federal and state holidays, weekends, and any day a company does not provide service to customers.
Friday is not a business day if your country or organization observes a 4-day workweek.
In the US, a business day refers to operating hours between 9 AM to 5 PM from Monday to Friday. When a colleague or employer uses EOD or COB in a conversation, they usually refer to this time frame.
Saturday, Sunday, and public holidays are not considered business days, even though some businesses stay open on Saturday or Sunday and during the holidays.
That said, this is not carte blanche—context still matters. While COB, in the strictest sense, only applies from Monday to Friday, EOD can include weekends in certain industries.
EOD in businesses that have daily operations applies on Saturday and Sunday. For instance, if you work in a shipping company that operates on Saturday, an order placed on 9 AM Saturday is a business day order.
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You’ve probably figured that the right way to use either COB or EOD depends on the context. Outside the time and location-based interpretation, every organization has its own internally agreed-upon definition.
If you are new to the business, ask your supervisor or confirm during onboarding.
As an employer, if you are using COB in an email to an employee for the first time, establish your preferred meaning. The employee may be too anxious to ask, and it will ensure you’re both on the same page.
Having said that, here are certain instances when you should use COD.
With many employees working from home, it can be tricky to figure out schedules. If you have clients in different states or countries, COB is a neutral term that works for you and them.
Since it’s pegged to 5 PM EST, each party will know the equivalent in their local time. Having a neutral time will avoid confusion and allow you to schedule meetings and assignments easily.
COB is particularly a better term if you work in an organization where you need to communicate with people worldwide. Wherever they may be, everyone is working within the same time frame.
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In this scenario, the interchangeable nature of both terms is beneficial. If the project or client is on eastern standard time, there’s no need to introduce a new meaning.
Use COB to communicate deadlines to team members clearly. It is also an appropriate term for American clients or clients who live in EST when you need them to share some information at the end of the day.
If the conversation references the end of the day’s trading session in a financial market or accounting process, COB is most appropriate.
Business professionals generally think of COB in terms of the New York stock exchange, i.e., 5 PM EST when the markets have ended regular trading hours.
In this scenario, even if you are in different time zones, COB works as a quick and effective way to communicate deadlines or set meetings.
If both of you are on the west coast, in this context, it wouldn’t matter that COB is 2 PM in your local time. You know intuitively that it means 5 PM EST.
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So far, we’ve learned that EOD is more subjective and could refer to your time zone or the sender’s. Most times, the sender’s time zone takes precedent since they are speaking from their time zone unless they state otherwise.
Based on common interpretation, the best time to use EOD is when you are referring to your specific time zone. Ideal scenarios would be –
The best time to use EOD in conversation is when the primary timeline is in your time zone. Deadlines are the arbitrary enforcer of corporate productivity. When you set deadlines, to avoid confusion, confirm that your time zone is the frame of reference to prevent miscommunication.
When used this way, EOD is most appropriate for assigning deadlines to employees without having to write lengthy sentences. They understand the deadline is at the end of your business day, even if they are in a different time zone.
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There’s no need to reinvent the wheel if your clients are in the same city, state, or general time zone as you. Since you’re using the same framework, there’s no need to introduce another layer of meaning.
Use EOD when you want to inform them you’ll send projects at the end of the business day. Since you’re in the same time zone, there’s no reason for either party to misinterpret the meaning.
Notice how I haven’t used a specific hour? EOD could be 2 PM, 4 PM, or 5 PM depending on where you are.
The appropriate time to use EOD is when you – the sender – and the message’s recipient live in a shared time frame.
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As shown thus far, there are distinct differences between COB and EOD on paper and there are different scenarios where they are applicable. The default meaning is evident even in certain environments without an agreed-upon definition.
But in the real world, things can quickly get messy. Individuals have unique cultural experiences that influence the interpretation of workplace terms.
Even in scenarios where both terms have precise generally-accepted meanings, things can still get messy.
Say an organization agrees COB means the end of the normal workday; when you factor in work from home schedules, the time definition of “workday” changes. Does a workday really start at 9 AM to 5 PM in remote work? No.
Additionally, COB and EOD are commonly used when assigning deadlines. Still, it is easy for people to revert to thinking in terms of their time zone.
Hundreds of missed deadlines result from one party assuming they have a few more hours to spare because their default working schedule is based on their time zone, not the manager’s.
The solution to this? Don’t use EOD or COB at all. Delete it from your workplace vocabulary.
Instead, be specific. State the time and time zone, like 6 PM EST or 2 PM CST. It is exact, unambiguous, and doesn’t require the recipient to remember the full context to interpret it correctly.
If you want some flexibility in the deadline, you can say something like “this evening” or “later today.” They aren’t super specific, but they have a clear time frame that avoids confusion.
But as mentioned earlier, the allure of acronyms in professional settings is undeniable. If you would still like to use EOD or COB, here are some examples to follow.
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When you are establishing it in a conversation for the first time:
You did a fantastic job on ABC’s report. Your suggested growth strategies were particularly inspiring. Please have XYZ’s quarterly analysis ready by COB on Friday.
Note: COB is 5 PM EST”
You did a fantastic job on ABC’s report. Your suggested growth strategies were particularly inspiring. Please have XYZ’s quarterly analysis ready by COB (5 PM EST) on Friday.”
When setting a deadline for employees in the same time zone:
“Please send your invoice for the month by COB Wednesday so we can process your payment as quickly as possible.”
“Hi Team, here are our following tasks for the week:
- Upgrade C-Suite network – due Wednesday COB
- Onboard new Sales team members – Friday COB”
When you’re using it for the first time, and they are in a different time zone:
I had a good time reminiscing about our high school years with you earlier. Please send me your resume by EOD today, Eastern Standard Time.”
When you mean the end of the literal day:
“Could you have a look at our budget proposal for the strategy meeting sometime before EOD tomorrow? I will greatly appreciate it.”
When you want to set a deadline for employees in the same time zone:
I just got off the phone with the client. They were delighted with your work. Keep it up.
Please can you have the monthly sales report ready by EOD? I want to approve it before leaving for my vacation.
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These tips will ensure effective communication if you use these acronyms in your workplace conversation.
Never assume your audience shares your meaning. Be specific all the way. For instance, to millennials, EOD is interpreted as permission to take work home and submit it later in the evening.
If you prefer them to complete the work before leaving the office, you must be more specific. That said, it is important to remember that people do their best work when they are free to work when they choose.
When you establish the meaning of COB or EOD for your company, be consistent with it in internal and external communication.
Your employees won’t have to ask for the exact meaning every time the term pops up in conversation. Externally, it will reduce the frequency of miscommunication between clients or suppliers, and everyone will know what to expect.
COB and EOD are the common acronyms, but they are not the only ones used to specify a time frame or set a deadline. Some organizations use other three-letter terms in place of COB or EOD. Others use them together.
These alternative workplace acronyms include:
When professionals use COP to set a time frame, they mean the strictest meaning of COB. It relates directly to the end of regular trading hours.
Example: “Please make sure the press release goes out before the COP tomorrow. I want us to capitalize on the goodwill as much as possible.”
Another acronym a business professional might use instead of COB or EOD is EOP. Like COP, it means the same as the stock market meaning of COB.
When used, it refers to the closing of the financial markets.
Example: “What do you think about exiting our position in CED by EOP tomorrow? Let me know what you think before EOD.”
EOB refers to the end of a standard workday. It is a direct alternative to EOD, but you can use it in place of COB too. Like EOD, the “business day” applies to the organization’s specified working days.
Example: “Please inform the rest of your team that the entire office is going out for drinks at EOB.”
To recap, COB means the close of business, and it refers to traditional closing hours, which is usually 5 PM EST. EOD means after the close of work as defined by the local business hours. EOD can also sometimes mean “any time before 11:59 PM.”
That said, it is advisable to avoid these terms as much as possible and use specific language instead. They will make your writing plain and direct. But if COB and EOD remain a part of your vocabulary, understanding their meaning and differences is the key to success.
Clear communication is integral in an efficient workplace or smooth client relationship. Unambiguous expectations and well-defined time frames prevent confusion and stress among employees.
Cassie Riley has a passion for all things marketing and social media. She is a wife, mother, and entrepreneur. In her spare time, she enjoys traveling, language, music, writing, and unicorns. Cassie is a lifetime learner, and loves to spend time attending classes, webinars, and summits.