Most healthy adults spend about 10–25% of their total sleep time in deep sleep, which usually works out to roughly 1–2 hours per night if you’re sleeping 7–9 hours.

What Is “Enough” Deep Sleep?

  • Sleep organizations and medical sources generally describe a normal deep sleep range of about 10–25% of total sleep in adults.
  • For a typical 7–8 hour night, this usually means around 60–120 minutes of deep sleep, with many experts converging on about 1.5–2 hours as a common target.

How Much Deep Sleep Should You Aim For?

  • If you regularly get 7–9 hours of sleep and your tracker shows about 1–2 hours of deep sleep, that is generally considered within a healthy range.
  • Some medical and sleep-medicine sources frame this as “about 20–25%” of sleep for many adults, or roughly 60–100+ minutes in an 8‑hour night.

Why Deep Sleep Matters

  • Deep sleep (slow‑wave sleep) is when the body does a lot of physical restoration: tissue repair, immune support, and energy recovery for the next day.
  • It also plays a key role in memory consolidation and feeling refreshed; too little may leave you groggy even if your total hours in bed look okay.

Normal Variations and Age

  • The percentage of deep sleep naturally changes with age: younger people tend to get more deep sleep, while older adults often get less even if total sleep time is similar.
  • Night‑to‑night variation is normal too, so a few lower‑deep‑sleep nights are usually not a concern if your overall energy, mood, and functioning feel stable.

When to Be Concerned

  • Consistently getting only a small fraction of that range (for example, ~45 minutes or less of deep sleep on typical adult sleep durations) may leave you feeling tired and is often described as “not enough” in medical articles.
  • If you feel persistently unrefreshed, foggy, or very sleepy during the day despite spending enough time in bed, it is best to discuss this with a doctor or sleep specialist, as conditions like sleep apnea or insomnia can reduce deep sleep.

Information gathered from public forums or data available on the internet and portrayed here.