How Many Hours of Sleep Do You Really Need? — 2026 Guide
By MySleepCalculator Editorial Team
Last updated: Jan 1, 2026
Sleep needs vary by age, health, and lifestyle. This guide summarizes what research says about how many hours of sleep you need and what happens when you get too little or too much.
Sleep Recommendations by Age
Experts generally recommend: newborns 14–17 hours, infants 12–15, toddlers 11–14, preschoolers 10–13, school-age children 9–11, teenagers 8–10, adults 7–9, and older adults 7–8. These are ranges; your own needs may sit at the higher or lower end based on genetics, activity, and health.
Why 7–9 Hours for Adults?
In 7–9 hours, most adults complete 5–6 full sleep cycles of about 90 minutes each. That allows enough deep sleep and REM for recovery, memory, and mood. Regularly getting less than 7 hours is linked to higher risk of heart disease, weight gain, and poor focus; consistently sleeping much more than 9 hours can sometimes signal or contribute to health issues too.
Quality and Timing Matter
It’s not only total hours. Waking at the end of a sleep cycle (instead of in the middle of deep sleep) can make the same duration feel more restorative. Our sleep calculator helps you plan bedtime and wake-up time around 90-minute cycles so you get the most out of the hours you sleep.
Signs You’re Not Getting Enough
Daytime sleepiness, needing caffeine to function, mood swings, trouble concentrating, and getting sick often can all point to insufficient sleep. If you have the time but still feel tired, focus on consistency and cycle-based timing—our calculator can help with the latter.
Finding Your Number
Pay attention to how you feel on different amounts of sleep (e.g. 7 vs 8 hours) when you wake at a cycle-friendly time. Use the calculator to see options for 4, 5, and 6 cycles and adjust based on your schedule and how you feel. You can also set a quick browser alarm from your selected time.