840 is a London-based concert series curated by the composers Alex Nikiporenko and James Luff. The series is dedicated to providing a platform for new experimental and minimal music. Each concert focuses on a particular chamber instrumentation, showcasing a diversity of works by living composers.

Since its launch in 2015, the series has attracted the attention of The Guardian and BBC Radio 3, and received generous support from the Arts Council, Hinrichsen Foundation and the RVW Trust. Works commissioned by 840 have been shortlisted for the BASCA Composer Award 2016, ISCM World Music Days 2018 and have received numerous further performances.

840 takes its name from Erik Satie's inscription in Vexations - "In order to play the theme 840 times in succession, it would be advisable to prepare oneself beforehand, and in the deepest silence, by serious immobilities."

Composer Nicholas Peters co-founded and co-curated the series from 2015 until 2017.