Say it like this
- Please confirm by COB today.
- We'll send the revised quote by COB Thursday.
- COB London time, please.
Use it at work
Setting a deadline
- Please send your comments by COB Friday.
- We need approval by COB today to hit the release date.
Promising a reply
- I'll get back to you by COB.
- You'll have the revised numbers by COB tomorrow.
Clarifying
- Is that COB your time or ours?
- Just to confirm, COB means 5 pm London time?
Don't say this
Use "by" with deadlines.
Don't mix it up
| Term | What it is | Who writes or uses it | When |
|---|---|---|---|
| COB | end of office hours | finance, legal, formal email | formal same-day deadlines |
| EOD | end of the working day | everyone, more casual | everyday deadlines |
| EOW | end of the working week | everyone | deadlines later in the week |
Practice
Try it
4 quick exercises
1. You are writing to a client in finance. Which deadline sounds most natural?
2. Legal asked us to return the signed contract by _______ Thursday.
3. Which sentence uses COB correctly?
4. Rewrite for a client in another time zone: 'Send it by COB.'
Say it out loud
Phrase 1 of 3
"Please confirm by COB today."
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More about COB
Real examples(3)
- in a client email
"Could you return the signed agreement by COB Friday?"
- in a finance team message
"All expense reports are due by COB on the 25th."
- in a project update
"Legal will share their comments by COB tomorrow."
More mistakes(2)
Handle with care. COB is local time by default. Name the time zone when your team or client is in another region.
- ✕COB means midnight.✓COB means the end of office hours, around 5 to 6 pm.
Business closes at the end of the working day, not at midnight.
- ✕Please send by COB. (to teams in New York and Bangalore)✓Please send by COB New York time (5 pm ET).
COB is local. Name the location or time zone.
Other forms(2)
- close of business full form
"Please reply by close of business on Friday."
- COB Thursday with a day
"The window closes COB Thursday."
Often used with(3)
- by COB · the usual deadline phrase
- COB today · today's end of office hours
- COB + city / time zone · makes the deadline clear for global teams
Similar words(3)
- EOD (end of day) · almost the same, a little more casual
- end of business day · full, formal phrase
- by 5 pm · the clearest option
Opposites(2)
- start of business
- first thing in the morning
Questions(4)
- What is the full form of COB?
- COB stands for "close of business".
- What time is COB?
- The end of normal office hours where the sender works, usually 5 or 6 pm.
- Is COB the same as EOD?
- Almost. Both mean the end of the working day. COB sounds more formal and is more common in finance, legal and government.
- What does COB mean in banking?
- In banking, COB often means the end of the processing day: payments after this time are handled the next business day.
