Later today refers to a time after now on the current day. By tomorrow sets a latest time linked to the next day, but it may not show whether the cutoff is morning, close of business, or the end of the day. Use a precise time when work depends on it.
“I’ll send an update later today.”
“Can you finish this by tomorrow?”
Both give a broad time window. Neither states a clock time or time zone.
What does later today imply?
Later places the event after now. Today keeps it within the current local calendar day.
At work, later today often suggests the speaker's remaining work hours, not 11:59 p.m. It does not name an exact deadline, and local habits may differ.
The phrase may express an intention, not a firm deadline:
“I hope to look at it later today.”
Hope to signals uncertainty. Compare the firmer statement:
“I will send it by 4:00 p.m. today.”
The second sentence gives a latest time, as long as both people share the zone or the writer states it.
What does by tomorrow imply?
The preposition by marks a latest point: at or before a stated time. Tomorrow names a day, not a single point in that day.
Some people read by tomorrow as before tomorrow begins. Others read it as sometime tomorrow, often by the end of the workday. Context and regional or workplace habits may help, but they do not remove all ambiguity.
Compare:
“Please send it by 9:00 a.m. tomorrow.”
“Please send it by the end of your workday tomorrow.”
“Please send it before tomorrow's 2:00 p.m. review.”
Each version makes the operational need clearer.
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Start a session →What might you hear at work?
“I’ll get back to you later today.”
The speaker signals a same-day response but does not name an hour. For the social meaning of that phrase, see whether “I’ll get back to you” is a promise or polite delay.
“We need approval by tomorrow.”
Ask when the approval must arrive for the next step to begin.
“Can we discuss this later?”
Unlike later today, plain later may refer to another day. Ask for more detail if timing matters.
“I’ll do it tomorrow.”
This places the action tomorrow. It does not necessarily state when the finished result will arrive.
What can you say naturally?
To clarify:
“What time tomorrow does the next step depend on?”
“Does later today mean before you sign off?”
To commit:
“I’ll send the update by 3:00 p.m. Eastern time today.”
To give an honest estimate:
“I expect to have an answer tomorrow afternoon. I’ll confirm the time after the technical review.”
To state the dependency:
“We need approval by 11:00 a.m. tomorrow so production can begin at noon.”
Use real operational times in actual messages. Do not turn sample times into artificial deadlines.
Today and tomorrow depend on location
At one instant, it can be Tuesday in California and Wednesday in Japan. In a message between those places, “later today” may refer to different dates.
Prefer a spelled-out date:
“I’ll respond Wednesday, October 7, by 4:00 p.m. Pacific time.”
For a distributed audience, add a date and time zone. A reader may also open an asynchronous message after “today” has passed.
Numeric date formats vary. Spell out the month or use the organization's agreed format.
Midnight and end-of-day problems
By midnight tomorrow can be read as the start or end of tomorrow. Say 11:59 p.m. on [date] or give another exact time. When possible, choose a cutoff within normal working hours.
By EOD tomorrow adds workplace context but may still leave the time zone and cutoff unclear. See EOD versus COB.
An after-hours deadline may create an expectation of late work. Managers should explain the business need and confirm that the timing is feasible and consistent with policy.
Recognition versus production
When you hear later today, expect the current local day, but ask for a time if you need the result. With by tomorrow, ask which point tomorrow is the cutoff.
When you write, choose the level of detail the task needs:
- casual: “I’ll look later today” when no one depends on the timing;
- operational: “I’ll update you by 4:00 p.m. today”;
- international: “I’ll update you by 4:00 p.m. Eastern time on October 7.”
For early-day priority language, see what “first thing” means at work. For ambiguous weekday references, see which Friday “next Friday” means.
The practical takeaway
“Later today” points to the rest of the current day. “By tomorrow” gives a latest time linked to the next day, but the cutoff may be unclear. For dependent work, confirm the date, time, zone, and reason for the deadline.