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Rachel Riley

Rachel Riley is a British television presenter and mathematician best known as the resident mathematician on Channel 4’s "Countdown" and its spin-off "8 Out of 10 Cats Does Countdown".

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 27, 2026|2 min read| Fact-checked

Rachel Riley is a British television presenter and mathematician best known as the resident mathematician on Channel 4’s "Countdown" and its spin-off "8 Out of 10 Cats Does Countdown". She has also presented other UK television programmes and has become known for campaigning against antisemitism and for Holocaust education.

Early life and education

Rachel Riley was born in 1986 in Rochford, Essex, England, and studied mathematics at Oriel College, Oxford. Sources describe her as having earned an MA from Oxford.

Television career

Riley became known through her role on "Countdown" after joining the programme in 2009. She later worked on other television projects, including "The Gadget Show", "It's Not Rocket Science", and "8 Out of 10 Cats Does Countdown".

Public activism

Riley has spoken publicly against antisemitism and has been involved in Holocaust education campaigning. Her advocacy was recognised with an MBE in 2023 and the Freedom of the City of London in 2025.

Personal life and public profile

Riley has also appeared as a contestant on entertainment programmes such as "Strictly Come Dancing". Her public profile combines television presenting with science communication and campaigning.

Key facts

  • Rachel Riley is a British television presenter and mathematician.
  • She is best known as the resident mathematician on Channel 4’s "Countdown".
  • She has presented other UK television programmes including "The Gadget Show" and "It's Not Rocket Science".
  • She is known for campaigning against antisemitism and for Holocaust education.
  • She received an MBE in the 2023 New Year Honours and the Freedom of the City of London in 2025.

Frequently asked questions

Who is Rachel Riley?
Rachel Riley is a British television presenter and mathematician best known for "Countdown" and "8 Out of 10 Cats Does Countdown".
When was Rachel Riley born?
She was born on 11 January 1986.
What is Rachel Riley best known for?
She is best known as the resident mathematician on Channel 4’s "Countdown".
What TV shows has Rachel Riley presented?
She has co-presented "The Gadget Show" and "It's Not Rocket Science", and has appeared on "Countdown" and its spin-off.
Has Rachel Riley received any honours?
Yes. She received an MBE in the 2023 New Year Honours and the Freedom of the City of London in 2025.
What is Rachel Riley’s connection to activism?
She is known for campaigning against antisemitism and supporting Holocaust education.

References

  1. Wikipedia — https://en.wikipedia.org/wiki/Rachel_Riley
    Supports: Birth date, birthplace, education, occupation, career on Countdown, other presenting roles, MBE, and Freedom of the City of London.
  2. BBC — https://www.bbc.co.uk/programmes/profiles/2J7DDtqQCHxDw8tct5spCQz/rachel-riley
    Supports: Her role on Countdown, lack of prior television experience before joining, and background in mathematics at Oxford.
  3. HELLO! Magazine — https://www.hellomagazine.com/profiles/201310081067/rachel-riley/
    Supports: Her early career on Countdown, The Gadget Show, and Strictly Come Dancing.
  4. JLA — https://www.jla.co.uk/presenters/rachel-riley/
    Supports: Summary of her presenting work and public advocacy on maths, science, and antisemitism awareness.