First vs Firstly

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

First

Top 1,000 (very common) A1

Firstly

Formal Top 3,000 (common) A2 adverb

Most formal: Firstly Most common: First

	First	Firstly
Pronunciation	🇬🇧 /["/fɜːst/"]/ 🇺🇸 /["/fɜːrst/"]/	🇬🇧 /["/ˈfɜːstli/"]/ 🇺🇸 /["/ˈfɜːrstli/"]/
Meaning	The one that comes before all others in time or order.	At the start of a list or explanation.
Example	She was the first person to arrive at the party.	There are two reasons for this decision: firstly…
Register	Neutral	Formal
How common	Top 1,000 (very common)	Top 3,000 (common)
CEFR level	A1	A2
Part of speech		adverb
Collocations	first step, first impression, first place, first time	firstly and secondly, firstly then, firstly I would like
Antonyms	last, final	lastly, finally
Common mistakes	Confused with 'foremost' in terms of importance., Using 'first' in place of 'one' for counting., Saying 'the firstest' instead of 'the first'.	'Firstly' is not often used in informal contexts., Some learners confuse 'firstly' with 'first,' thinking they can use them interchangeably in all situations., Overusing 'firstly' when listing items can sound overly formal.
Usage notes	Use 'first' when talking about the beginning of a sequence or the earliest occurrence. It's neutral and widely applicable in discussions, writing, and instructions. Avoid using it in overly formal contexts where 'primary' might be more suitable.	Use 'firstly' to introduce the first point in formal writing or speeches. Avoid in casual conversations; 'first' is often preferred instead.

See it in real clips

Game Of Thrones › S1 E1

I heard you the first time.

Look, I'm the first one to say that.

Agatha Christies Poirot › S1 E1

But first, Scotland Yard.

Game Of Thrones › S1 E1

I heard you the first time.

Look, I'm the first one to say that.

First

The Lord Of The Rings › The Fellowship Of The Ring

Do you know how the Orcs first came into being?

Firstly

Frequently asked questions: First vs Firstly

What's the difference between First and Firstly?

First: The one that comes before all others in time or order. Firstly: At the start of a list or explanation.

Which is more formal: First and Firstly?

Firstly is the most formal of these.

Which is more common: First and Firstly?

First is the most common in everyday English.

Which is more advanced: First and Firstly?

Firstly is the highest level, at A2, on the CEFR scale.

Are First and Firstly the same CEFR level?

First: A1, Firstly: A2 on the CEFR scale.

Can you show an example of each?

First: She was the first person to arrive at the party. Firstly: There are two reasons for this decision: firstly…

Can I use First and Firstly interchangeably?

Not always. First and Firstly 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.