Simultaneously vs While I'm doing this

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

Simultaneously

Top 2,000 (common) C1 adverb

While I'm doing this

Beyond 10,000 (less common)

Most common: Simultaneously

	Simultaneously	While I'm doing this
Pronunciation	🇬🇧 /["/ˌsɪmlˈteɪniəsli/"]/ 🇺🇸 /["/ˌsaɪmlˈteɪniəsli/"]/	🇬🇧 //waɪl aɪm ˈduːɪŋ ðɪs// 🇺🇸 //waɪl aɪm ˈduɪŋ ðɪs//
Meaning	At the same time as something else.	At the same time as I am doing this
Example	The game will be broadcast simultaneously on TV and radio.	While I'm doing this, could you please finish the report?
Register	Neutral	Neutral
How common	Top 2,000 (common)	Beyond 10,000 (less common)
CEFR level	C1	-
Part of speech	adverb
Collocations	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	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 '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

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: Simultaneously vs While I'm doing this

What's the difference between Simultaneously and While I'm doing this?

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

Which is more common: Simultaneously and While I'm doing this?

Simultaneously is the most common in everyday English.

Can you show an example of each?

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 Simultaneously and While I'm doing this interchangeably?

Not always. 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.