How the focus time calculator works
Meetings remove time from the day directly. Interruptions cost more than the moment they take, because it takes time to rebuild concentration afterwards.
Time lost = Available time × Interruptions per hour × Refocus minutes ÷ 60
Focus time = Available − Lost
The default refocus time of 23 minutes comes from research by Gloria Mark at the University of California, Irvine, which found people took about 23 minutes on average to return to an interrupted task. Real recovery varies: a quick question may cost a few minutes, while a context switch to a different project can cost much more. Treat the result as a rough indicator of how fragmented your day is.
Worked example
An 8-hour day with 2 hours of meetings leaves 6 hours. One interruption an hour, each costing 23 minutes to recover from, eats 2.3 hours, leaving about 3.7 hours of focus (46% of the day), or 18.5 hours a week. Batching messages to cut interruptions to one every two hours would add over an hour of focus a day.
Frequently asked questions
How long does it take to refocus after an interruption?
Gloria Mark's research found an average of about 23 minutes to return to the original task.
How much deep work can a person do in a day?
Cal Newport suggests about 4 hours is a realistic ceiling for intense focus for most people.
Do meetings count as deep work?
Usually not; deep work is uninterrupted, cognitively demanding solo work.
How can I reduce interruptions?
Use status messages, office hours for questions and do-not-disturb modes during focus blocks.
Updated October 2026. Results are estimates for education, not financial or medical advice. All math runs in your browser; nothing you type is sent anywhere.