COB vs. EOD: What’s the Difference?

Companies use different acronyms and initialisms in their communications for many reasons. COB and EOD are common initialisms organizations and managers use to denote due dates, but what do they mean? And when should a person use one or the other? This story lays out the differences between close of business and end of day and specific use cases for each one. 

Business acronyms and initialisms make communication and emails a bit easier for in-groups. But for new professionals who have not learned the lingo, they can sometimes lead to confusion. Nowhere is this more apparent than when a supervisor or client asks a task to wrap up by COB or EOD. In a fully connected world, failure to understand the distinction between these two acronyms can lead to missed deadlines and unhappy clients or bosses.

So, what do COB and EOD mean? And how do organizations ensure clarity of communication when using them? 

What is COB?

When a person or company uses “COB,” they mean “close of business.” COB’s meaning refers to the end of a business day based on the closing of financial markets in New York City. Most American businesses use it to set deadlines for task completion by 5 p.m. in the Eastern time zone.

What is EOD?

EOD stands for “end of day.” Businesses use EOD to set deadlines for tasks due by the end of the business day. Most commonly, this is 5 p.m. If no one specifies a time zone, it usually means the end of the day in the sender’s time zone.

What Are Business Days?

Companies typically define business days as Monday through Friday. Many businesses operate between 9 a.m. and 5 p.m. on these days. The exceptions to this rule are legal public holidays. The most common legal holidays — as noted by the United States legal code — include:

• New Year’s Day, January 1
• Presidents Day, the third Monday in February
• Memorial Day, the last Monday in May
• Juneteenth, June 19
• Independence Day, July 4
• Labor Day, the first Monday in September
• Columbus Day, the second Monday in October
• Veterans Day, November 11
• Thanksgiving Day, the fourth Thursday in November
• Christmas Day, December 25

Some businesses’ preferred holidays differ, but most companies adhere to the above schedule. Other businesses may operate 24 hours per day or even on Saturdays. Even if a business is open on Saturday or Sunday, most companies do not consider the weekend days “business days.” 

When to Use COB

Clear communication is one of the most important aspects of running a successful business, so knowing when and how to use COB or EOD saves a lot of headaches. This is especially true when working with business partners across countries and time zones.

COB is useful when assigning work to employees in different time zones. COB can be a neutral time for both parties to submit work or schedule a meeting. Because most professionals regularly use COB as a well-known acronym, it makes sense.

Because so much of the business world operates on Eastern time, COB also works when completing assignments or deliverables for clients in that time zone. Communicate deadlines to these clients or partners using COB with the addition of Eastern time.

Conversations that reference accounting or financial markets also typically refer to COB as 5 p.m. Eastern.

Some examples of COB in communication include:

• “Please submit the budget proposal for the market strategy by COB (5 p.m. EST).”
• “Please send the relevant brand guidelines by COB Tuesday.”

When to Use EOD

When does EOD fit better with company goals? It usually works best when communicating information to employees or clients familiar with the time zone in which the sender lives or works. Most professionals use EOD to set deadlines for specific business days. 

EOD also makes the most sense when talking to local clients. This shared framework reduces ambiguity when referring to the end of the business day because it typically happens for both parties simultaneously. Examples of EOD usage include:

• “Prepare and send client slide deck before Monday EOD.”
• “Apply edits to the news release by Wednesday EOD.”
• “Publish blog post due Thursday EOD.”

Similar Abbreviations in Business

Some professionals use other initialisms when listing deadlines. These terms may take the place of COB or EOD or function in conjunction. Other typical workplace acronyms can include:

• EOB (end of business day): Some companies combine COB and EOD to represent the end of the workday. It is also interchangeable with both EOD and COB.
• COP (close of play): COP refers to the closing of financial markets and thus often replaces COB in business correspondence.
• EOP (end of play): Much like COP, this term refers to financial markets closing and replaces COB.

How to Ensure Clear Communication Across Multiple Time Zones

Acronyms and initialisms streamline communication and reduce lengthy emails, but they may not always be the best fit for a conversation. In many cases, clearly stating times — including time zones — to communicate deadlines and expectations reduces friction. 

Ultimately, the best way to use acronyms and initialisms in professional correspondence is to know the intended audience and set clear guardrails in documentation and onboarding.

Top Takeaways

• Companies use different acronyms to denote deliverable due dates.
• End of day (EOD) refers to the end of the business day.
• Close of business (COB) typically refers to the end of the trading day in Eastern time.
• EOD usually refers to the end of the business day in the sender’s time zone.
• Clear communication about due dates reduces friction and misunderstandings about when items are due, even across time zones.

(Reporting by NPD)