Bedtimes, sleep debt, caffeine, insomnia, snoring, shift work — type your problem, get a straight answer in seconds. The full detailed report costs less than a cup of coffee: $2.95.
'Everyone needs eight hours' is the most repeated falsehood in sleep science. Your real need is a range that shifts with age — teenagers genuinely need more than their parents, and older adults genuinely need less — and quality matters as much as quantity. This calculator gives you your age-based target range and the honest test for whether you are hitting it.
The '8 hours' rule is a myth with a grain of truth — your real need depends on age and how you function. This calculator gives your evidence-based range.
Most adults function best on 7-9 hours; the exact number sits inside that range and is found by testing a fixed schedule for two weeks.
Yes — 8-10 hours. Their body clock also shifts later in puberty, so an early school start fights their biology daily.
Judge by daytime function: stable energy, no mid-day dozing, no weekend catch-up of more than an hour — not by the clock alone.
Every tool answers instantly from our own knowledge and calculators. Want the deeper, personalised version? Each has a $2.95 full report.