The use of abbreviations in any form of business has become usual nowadays.

Whether you are working in a small or large company, you will notice that they are being widely used. In this article, we will explain two probably the most confusing acronyms there are.

It’s not their general term, but their similarity which confuses people. Some people even say their meaning is the same.

You would have probably guessed about which ones we are talking about even if it isn’t stated in the title. Without any further deferment let us begin and explain what both COB and EOD are and whether they have the same meaning.

So strap in and we can start our ride!


Means of communication have changed a lot throughout history. In the past, people waited for weeks, even months to get a message from their family, friends and business partners.

Sometimes, deliveries were late, due to, i.e. ship accident or a pirate attack. In those situations, both suppliers and customers usually didn’t know what had happened for weeks.

With the discoveries of new means of communication, everything changed.

In today’s world, doing business is much more dynamic than before. People can communicate with each other in a matter of seconds wherever they are, thanks to technological advancements. Mobile phones, e-mails, social media. News can travel from one side of the globe to another in a short period of time.

In this age of globalization, as businesses grew, the need for higher efficiency grew too. If you are not being efficient, you will fall behind your competitors.

Thus, every company needs to quickly adapt to any changes in their environment in order to survive in the highly dynamic business world.

One of the ways to achieve that is by being as productive as possible in your jobs. And since e-mails are widely used in every company as a fast way to inform everyone about anything that is happening.

Now, writing a lot of e-mails while working takes time, so the best way to reduce the time needed is the use of abbreviations. This method is used A LOT, and we really mean it. It is like another language is being used for communicating between employers and employees. Thus, it is really important to learn what each of them means.

But do not worry! It is like riding a bicycle. Once you learn them, you will know them forever.

Some of the acronyms are easily recognized, which makes them easy to use, but with the increasing use of them in a lot of companies, it is getting harder and harder to distinguish them if they are very similar.

That is why you need to prepare yourself if you are just starting to work in a company.

Be prepared to learn fast and adapt to the use of business language, since there will be a large number of terms which you will have to use in order to communicate with your colleagues and employers.


COB is an abbreviation used in business to emphasize the time in which something should be done. The full length of it means “close of business” and it represents the time when you are supposed to go home from work. So if your work time is, i.e. from 9:00 to 17:00 hours, that means COB is 17:00.

In short, it represents the end of a workday and can be used despite your timezone. If, for instance, you have an employee working in another time zone, you can use COB abbreviation to emphasize that the work has to be done by the end of the workday.

EOD is shortened term from “end of day”. Traditionally, it represents the time when you end your business day and go to sleep. It is also used to represent the same thing as COB, which means the end of a workday (17:00 hours). Apart from that, people often use it to represent the full workday, which lasts from the moment the work started (9:00) to the moment it starts again next day (9:00 next day) or as a way to mark full day as a whole, which means the end of day would be midnight.

Now you see why using these terms can be a bit confusing. In most companies, it is really important to finish everything on time, because some clients do not tolerate when someone is being late with their deliveries and reports.

Being late means losing a client, and losing a client means losing a revenue. If that happens continuously, more clients could be inclined to leave, which means your business could be ruined. That is why it is of utmost importance not to be late and not to miss your due dates and hours.

In order to do that, communication, not just between an employer and employee, must be clear, with the least amount of misunderstandings as possible so it wouldn’t come to the problems we had mentioned earlier.


As mentioned above, using these abbreviations can be a bit unclear and confusing at first glance. In order to avoid potential problems which can occur, you, as an employer should set a clear set of explanations of what each of the terms represents.

Of course, some of them are self-explanatory, but when we talk about ones which are not obvious, they should be listed so people wouldn’t make mistakes.

Now, as for when you should use abbreviations, it really depends on the company, employers, employees and the subject in question or the line of business. If you do work which requires your company to be precise in dealing with time-sensitive issues, perhaps it is better to communicate with your colleagues in a clear and direct way, without using too many abbreviations.

Or if you are working in a multinational corporation with people from all over the world, who work in different time zones, you might want to do the same thing and include the precise date and time for due dates, including the specific time zone in your message.

So, for example, let’s imagine you are a person working in Los Angeles and you need to communicate with a person called John from your company who is stationed in the company’s subsidiary in Stockholm. This is how your conversation should look like:

“Hello, John,

First of all, I wanted to say that you did an impressive work with our last client, they sounded very satisfied when I talked to them. Keep up the good work!

Second thing, the end of a first quarter is almost due, so could you please send me the quarterly sales report by the end of next week, let’s say Friday at 17:00 EST?

Looking forward to hearing from you.

Best regards,


By writing the exact day and time, including the time zone, John probably wouldn’t have a problem to deliver the needed report on time, because he wouldn’t be concerned with the possibility of making a mistake and missing a due date.

Of course, Brenda would’ve been able to use COB and EOD abbreviations if she had wanted to. Using COB wouldn’t have caused any issues since that abbreviation is clear enough. Close of business always means the end of work hours, so John would’ve known what the deadline is.

COB usually means the end of working hours in local time zone, so even if she hadn’t mentioned time zone in her email, John would’ve not been confused.


The story is a bit different when it comes to the usage of EOD. As we had mentioned before, “end of the day” has had multiple meanings so far, so in order for employers and employees to use it, a clear explanation of its meaning should be provided by the company or by a person who is writing an email.

Let us imagine the same situation as before, with one difference, that Brenda used EOD abbreviation instead of listing all the details. So this is how it would look like:

Hello John,

First of all, I wanted to say that you did an impressive work with our last client, they sounded very satisfied when I talked to them. Keep up the good work!

Second thing, the end of a first quarter is almost due, so could you please send me the quarterly sales report by the end of next week, let’s say by EOD next Friday, EST?

Looking forward to hearing from you.

Best regards,


You can notice that this message could be a bit confusing and you can guess why. By using the term EOD, Brenda informed John that she needs those reports for next Friday by the end of the day.  Now, if John is experienced enough and has been working in a company for some time, he will probably know what she meant by “end of the day”.

The problem can occur if John is a new employee who doesn’t yet understand the company’s terminology completely. He might be confused, asking himself what she meant by end of the day? Did she mean the end of the workday or the end of the day in general? Or did she mean as if EOD meant the time right before the start of a new workday?

All these questions he might be asking himself would be a complete waste of time and thus, a complete waste of John’s potential productivity.

He might also be afraid of asking her back what did she exactly mean by EOD, because he might be thinking that perhaps he should’ve already known that, and since she wrote him the message like that, she is expecting him to know what the abbreviation means.

All of this can have a very negative impact on business because it decreases the efficiency and productivity of workers and employers. Instead of thinking about their work, they would waste precious time to think about the context of a simple email. And that is something which should be avoided.

So, you might ask, in what situations you could use EOD then? Well, in cases where it is clearly defined what EOD really means, whether it is the end of the workday as we define COB, the end of the day as a whole (midnight) or the beginning of a new workday, you can use EOD abbreviation without causing a potential ruckus.

For example, if you and your employees knew that EOD means the start of a new workday, and if you needed your assistant to make an appointment with your client, email would look something like this:

“Hello  Jane,

Could you please make an appointment with Mr. Jones and inform him by EOD tomorrow?

Best Regards,


Now, in this case, Jane already knows what EOD means and won’t have a problem to make the necessary arrangements and notify both Brenda and Mr. Jones on time. The appointment will be made, Brenda will do her business with Mr. Jones and everyone will be happy.

If that hadn’t been the case and EOD abbreviation hadn’t been properly defined, then perhaps Jane would have made a mistake, both Brenda and Mr. Jones would have been given the wrong appointment time or they wouldn’t have been given the details on time and in the end both Brenda and Jane would’ve been in trouble, because client would’ve most likely gone to another company.

Of course, this is an extreme situation, it doesn’t happen every day that clients leave the company because of an email mistake, but the possibility is there, so people should have that thought in their minds while doing their jobs.


We’ve already mentioned that there is a large number of abbreviations which are being used in business. Since that is the case, while being used, some of them sort of mixed with each other and created new abbreviations, which are all basically the same. We are going to mention some of the most typical abbreviations which are often used as a substitute for EOD and COB.

Most of these acronyms, as you will notice, are sort of a mix of both EOD and COB. Some of them are different, but eventually, their meaning is altogether similar.

  1. EOB – “End of business”
  2. EOP – “End of play”
  3. COP – “Close of play”

As you can see, all of these basically has the same meaning. The only difference is where they are being used the most.

EOP and COP are mostly used in financial markets, to represent the end of the market transactions, or to be more precise the time when all the trading stops for that day and the market closes.

EOB or “end of business” has literally the same meaning as COB or EOD. It is a mix of two. So it represents the end of a workday, more precisely, the time when people stop their work and go home. We can say it represents the end of the shift for the people working in shifts.

There are a lot more acronyms used in business and in order for you to use them properly, you will have to learn them by heart and do the right judgment when it comes to using them, so you could properly decide when and where to use them.

That’s why it is important to learn the business language, so you don’t get in the situation where your excellent knowledge of English is somehow lessened with your poor knowledge of business terminology.


In this article, we learned something about using abbreviations in business, why it is sometimes a good thing and why it is sometimes a bad thing.

We learned what are the meanings of EOD or “end of the day” and COB or “close of business” abbreviations. Even though they are often used in the same context, we saw there is still a little difference between them and that it all depends on the way you are looking at them, whether they are explained and their meaning clarified or not.

The general answer to the question of whether you should use abbreviations or not is that you should avoid using them as much as possible, despite the fact they can be quite useful.

The reason is that they can often get misinterpreted and their meaning can be twisted and confusing in some cases, as we have already seen in our examples.

Because of that, most of the time it is better to write your emails and messages in full extent so you don’t confuse the person on the other side. When people are not confused, they can focus on their job and make fewer mistakes. This all leads to a rise in productivity and efficiency, which is what ultimately, leads to better performance of your company as a whole.

And companies with higher performance are respected and often recommended by other clients.

COB vs EOD: What Each Means and How to Use Them

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