How it counts
6, 5, or 4 cycles.
The calculator counts backward in 90-minute blocks, then leaves 15 minutes before the first cycle.
Real nights do not keep identical time. Use these as planning times.
Sleep calculator Tomorrow's energy starts with tonight.
Pick an alarm. We count back in about 90-minute blocks.
or
Your times will appear here.
Nothing is stored.
The evening bottle
Three capsules beside the last lamp.
Magnesium PM has 275 mg elemental magnesium. No melatonin is listed.
Explore sleep→→ See Magnesium PMWhy 90 minutes?
It is a common counting rule. Real sleep cycles can be shorter or longer.
Why add 15 minutes?
The calculator leaves 15 minutes before the first counted cycle.
Is anything saved?
No. The calculation runs in your browser.