Sleep & alertness
4 tools, including Caffeine intake calculator, Coffee vs. Sleep Calculator, Nap Calculator and Sleep cycle calculator. All free, with no account and nothing to install.
Caffeine intake calculatorEstimate a safe daily caffeine limit for a healthy adult.Coffee vs. Sleep CalculatorA transparent heuristic that scores a coffee against a nap for the alertness you need right now.Nap CalculatorBest nap wake-up times (or lie-down times) across common nap lengths, adding the time to fall asleep.Sleep cycle calculatorFind the best bedtimes to wake up refreshed, based on 90-minute sleep cycles.