At the same time vs Simultaneously vs While I'm doing this

When to use each in English, with meaning, register, and examples.

At the same time

Top 2,000 (common)

Simultaneously

Top 2,000 (common) C1 adverb

While I'm doing this

Beyond 10,000 (less common)

	At the same time	Simultaneously	While I'm doing this
Pronunciation	🇬🇧 //æt ðə seɪm taɪm// 🇺🇸 //æt ðə seɪm taɪm//	🇬🇧 /["/ˌsɪmlˈteɪniəsli/"]/ 🇺🇸 /["/ˌsaɪmlˈteɪniəsli/"]/	🇬🇧 //waɪl aɪm ˈduːɪŋ ðɪs// 🇺🇸 //waɪl aɪm ˈduɪŋ ðɪs//
Meaning	Occurring simultaneously or together.	At the same time as something else.	At the same time as I am doing this
Example	They left the house at the same time.	The game will be broadcast simultaneously on TV and radio.	While I'm doing this, could you please finish the report?
Register	Neutral	Neutral	Neutral
How common	Top 2,000 (common)	Top 2,000 (common)	Beyond 10,000 (less common)
CEFR level	-	C1	-
Part of speech		adverb
Collocations	do two things at the same time, speak at the same time, work at the same time, occur at the same time, feel at the same time	happen simultaneously, simultaneously occur, perform simultaneously	think while I'm doing this, feel free while I'm doing this, remember while I'm doing this
Antonyms	-	sequentially, consecutively, successively	-
Common mistakes	Confusing 'at the same time' with 'at the same moment'., Using it with only one subject., Placing it incorrectly in the sentence.	Using it incorrectly to mean 'separately'., Confusing it with 'simultaneous' which is an adjective., Misplacing it in a sentence which can alter the meaning.	Confusing with 'while doing this' which has a slightly different emphasis., Using in overly formal contexts where simpler phrases would suffice.
Usage notes	Use when describing events happening together. Avoid in very formal contexts; more suitable for everyday conversations.	Use 'simultaneously' to describe two or more actions happening at the same time. It works well in both spoken and written contexts but may sound overly formal in casual conversation.	Used to indicate concurrent actions. Suitable for casual conversation and informal writing but can also be used in semi-formal contexts.

See it in real clips

but at the same time, Alice is over there unconscious.

The Queen Gambit › S1 E1

At the same time.

- Why don't you tell him at the same time why ? - Don't worry, I will.

but at the same time, Alice is over there unconscious.

The Queen Gambit › S1 E1

At the same time.

At the same time

We create and perceive our world simultaneously.

We'd have to hit all banks simultaneously. SWAT teams, backup.

We create and perceive our world simultaneously.

We'd have to hit all banks simultaneously. SWAT teams, backup.

Simultaneously

- Quit fuckin' around and give her the shot. - While I'm doing this,

While I'm doing this

Frequently asked questions: At the same time vs Simultaneously vs While I'm doing this

What's the difference between At the same time, Simultaneously, and While I'm doing this?

At the same time: Occurring simultaneously or together. Simultaneously: At the same time as something else. While I'm doing this: At the same time as I am doing this

Can you show an example of each?

At the same time: They left the house at the same time. Simultaneously: The game will be broadcast simultaneously on TV and radio. While I'm doing this: While I'm doing this, could you please finish the report?

Can I use At the same time, Simultaneously, and While I'm doing this interchangeably?

Not always. At the same time, Simultaneously, and While I'm doing this are related and overlap in some contexts, but they differ in register, how common they are, and usage, so swapping one for another can change the meaning or tone. Check the differences above before substituting.