Time
Sleep time calculator
Find bedtime or wake-up options based on simple 90-minute sleep cycles.
LocalInputs stay in your browser
Suggested times
Choose a time and calculate.
How to use it
Enter your values, choose the options that match the task, then copy the result when you are done. The work happens in your browser.
Frequently asked questions
How are the times calculated?
The calculator uses 90-minute sleep cycles and adds a short settling-in buffer for bedtime suggestions.
Is this medical advice?
No. It is a simple planning aid for comparing possible sleep and wake times.