COB vs. EOD: What Each Means & How to Use Them

Business acronyms. They make lengthy emails easier to digest, lead to better communication skills, and make you feel a little like you’re communicating the instructions for a covert mission. However, acronyms can also be confusing and frustrating. Have you ever received an email from your boss or colleague asking to have a task completed by COB or EOD? If you’ve felt confused or nervous you’ll miss some unspoken deadline — you’re not alone.

So, what do these terms mean? And how can they be used correctly when communicating with your colleagues? First, let’s run through the definitions.

What does COB mean?

COB stands for “close of business.” It refers to the end of a business day and the close of the financial markets in New York City, which define U.S. business hours. It’s used in business communications to set a deadline for a task to be completed by 5:00 PM Eastern Standard Time (EST).

COB can be used interchangeably with end of business (EOB), end of day (EOD), end of play (EOP), close of play (COP), and close of business (COB).

What does EOD mean?

EOD stands for “end of day.” It’s used to set a deadline for a task that should be complete by the end of the business day — typically 5:00 PM. When no time zone is provided, end of day is relative to the sender’s time zone.

Acronyms used interchangeably with EOD include, end of business (EOB), end of play (EOP), close of play (COP), and close of business (COB).

What are Business Days?

Close of business (COB) and end of day (EOD) refer to a business day. But which days are considered business days? A business day refers to any workday — Monday through Friday — from 9:00 AM to 5:00 PM in the business’s local time.

Depending on the type of business or industry you work in, you may encounter 24-hour operations or working days on weekends. For example, banks and delivery services typically operate on Saturdays. This brings us to the following question:

Is Saturday considered a business day?

That answer is no. Most companies operating over the weekend do not consider Saturday or Sunday a “business day.” Public holidays are also usually not referred to as business days.

How to Use COB & EOD (with Examples)

If you’re using acronyms, such as COB and EOD, with individuals across countries and time zones, ensure clear expectations are set.

Let’s say you’re located at your company’s headquarters in New York but are working with an employee based in your London office. If this is the first time you’re collaborating with your London colleague, set communication guidelines for your interactions moving forward.

Share these expectations with the individual via video meeting, call, or email.

For example:

Hi Maddy,

It was great chatting with you earlier today about our marketing conference schedule for the year. Please send me your finalized projections by EOD (end of day) tomorrow, Eastern Standard Time.

Best,

Meredith

If there’s a deadline for an important project or task — it might be best to skip the acronyms altogether and provide your colleague with a specific date, time, and time zone.

For example:

Hi Justin,

I’m looking forward to the end-of-month presentation. Could you please provide me with your completed slides by Thursday, at 5:00 PM EST?

Thank you,

Meredith

Transparency and clearly communicated expectations and deadlines lead to less confusion and stress in the workplace. They also ensure tasks and projects are delivered on time. When in doubt, clarify your acronyms for better working relationships and successful results.

Want to simplify other confusing business correspondence jargon? Check out these articles on Best Regards vs. Kind Regards, Why You Need to Stop Using “Dear Sir or Madam,” As Per Our Conversation, and “Hope You’re Doing Well” Alternatives.