Deep work timer

How to use the online timer

Ninety minutes is a commonly cited length for a single block of deep, uninterrupted focused work — long enough to get well past the initial ramp-up period that any demanding task requires, and to actually reach a productive flow state, without running so long that concentration inevitably starts to fade regardless of how well-rested or motivated someone is.

The setup before this ninety minutes starts matters enormously, arguably more than for shorter blocks, since the cost of an interruption partway through is considerably higher — notifications off, the specific task decided in advance, and any obvious sources of interruption removed or at least anticipated, since a single unexpected interruption partway through a ninety-minute block can cost far more than the few minutes it appears to take.

Genuinely demanding cognitive work — writing, coding, detailed analysis — tends to suit this length far better than routine or administrative tasks, which rarely benefit from being stretched into long uninterrupted blocks and can often be handled in shorter windows instead. A proper break afterwards, away from a screen if the work involved one, matters for being able to do another block later in the day rather than running on fumes.