Which format do I need?

Memoir vs autobiography vs biography

Three ways to write a life. One is a story, one is a record, one is research.

Intermediate Assumes you can already draft and revise a piece.

People say "I'm writing my autobiography" when they mean a memoir, and the difference decides the whole shape of the book. An autobiography covers a life from start to now and is organised by time. A memoir takes one thread out of a life and is organised by meaning. A biography is about somebody else and is answerable to evidence you have to go and find.

Side by side

Memoir vs autobiography vs biography compared across six axes
	Memoir	Autobiography	Biography
In one line	One theme from a life, shaped like a story.	The whole life, in order, by the person who lived it.	Someone else's life, built from evidence.
Typical length	50,000–90,000 words	80,000–150,000 words	80,000–200,000 words
Who reads it	Someone who does not know you and does not need to — they are here for the theme	Someone already interested in you — which usually means you are already known	Someone interested in the subject, and willing to hold you to your sources
Voice	First person, close, literary. Scenes rather than summary.	First person, more measured, more summary than scene.	Third person. Interpretive but accountable — claims are cited.
Shape	Organised by meaning, not chronology. Time jumps freely if the theme requires it.	Chronological. Birth, formation, career, achievements, reflection.	Usually chronological, with thematic chapters where a strand needs following.
Use it when	You lived through something that will mean something to strangers.	There is public interest in the whole arc, not just one part of it.	You have access to archives, letters, interviews or records, and something new to say.

Memoir

One theme from a life, shaped like a story.

Typical length: 50,000–90,000 words

Who reads it: Someone who does not know you and does not need to — they are here for the theme

Voice: First person, close, literary. Scenes rather than summary.

Shape: Organised by meaning, not chronology. Time jumps freely if the theme requires it.

Use it when: You lived through something that will mean something to strangers.

Autobiography

The whole life, in order, by the person who lived it.

Typical length: 80,000–150,000 words

Who reads it: Someone already interested in you — which usually means you are already known

Voice: First person, more measured, more summary than scene.

Shape: Chronological. Birth, formation, career, achievements, reflection.

Use it when: There is public interest in the whole arc, not just one part of it.

Biography

Someone else's life, built from evidence.

Typical length: 80,000–200,000 words

Who reads it: Someone interested in the subject, and willing to hold you to your sources

Voice: Third person. Interpretive but accountable — claims are cited.

Shape: Usually chronological, with thematic chapters where a strand needs following.

Use it when: You have access to archives, letters, interviews or records, and something new to say.

Decide quickly

Which one do you actually need?

Your own life, one thread → memoir.
Your own life, all of it, in order → autobiography.
Someone else's life → biography.
You need footnotes → biography.
You are writing scenes with dialogue you remember → memoir.
Nobody has heard of you yet → memoir. Autobiographies by unknown people rarely find publishers; memoirs by unknown people do, when the theme is strong.

Common confusions

The questions that come up every time.

How accurate does memoir have to be?

The events must be true. Dialogue may be reconstructed — no one remembers exact words from thirty years ago, and readers accept this. What you cannot do is invent events, merge people into composites without saying so, or move things in time to improve the story. Memoirists have lost careers over exactly that.

What about the other people in my memoir?

They did not consent to being written about, and this is the hardest part of the form. Legally, you face defamation risk for false statements of fact and privacy risk for true private ones. Practically, ask whether each person is there because the theme needs them or because you are still angry. Many memoirists change identifying details and say so in a note.

Can a biography be about someone living?

Yes, and it is much harder. Living subjects can sue, refuse access, and pressure sources. An authorised biography buys access at the cost of independence; an unauthorised one keeps independence and loses the archive. Decide which before you start, not halfway through.

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