Sleep cycles
Children’s sleep cycles
A cycle lasts 50 minutes in a newborn and 90 minutes in an older child. Between two cycles everyone goes through a very short awakening — which explains a great many night wakings.
Reference table by age
| Age | Cycle | Night | Over 24 h |
|---|---|---|---|
| 0 – 2 months* | 50 min | — | — |
| 2 – 6 months | 60 min | 8–9 h | 12–16 h |
| 6 – 12 months | 70 min | 11–12 h | 12–16 h |
| 1 – 2 years | 70 min | 11–12 h | 11–14 h |
| 2 – 3 years | 75 min | 10–11 h | 11–14 h |
| 3 – 5 years | 90 min | 9–10 h | 10–13 h |
| 6 – 12 years | 90 min | 9–12 h | 9–12 h |
| 13 – 18 years | 90 min | 8–10 h | 8–10 h |
“Night” means night-time sleep alone (Réseau Morphée). “Over 24 h” is the total recommended by the American Academy of Sleep Medicine, naps included. * Before 4 months the AASM publishes no recommendation, the variability being too great. Around 3–4 years Réseau Morphée observes cycles of up to 120 min: the 90 min used here is the adult cycle, reached around 4–5 years.
How long does a sleep cycle last?
Sleep does not run in one block: it comes in cycles, and each cycle moves through light sleep, deep sleep, then REM sleep. Cycles grow longer with age, from 50 minutes in a newborn to 90 minutes around 4 or 5 years — the adult cycle length, which stays put from then on.
A very brief awakening comes at the end of every cycle. A child who can fall back asleep alone carries on into the next cycle without anyone noticing; one who cannot yet calls out. This is not a sleep disorder, it is how a night works.
What these landmarks are good for
Knowing how long a cycle lasts lets you read a night differently: a waking that lands exactly two hours after bedtime is not a whim, it is the end of a cycle. And a child woken in deep sleep will take far longer to surface than one caught at the end of one.
These are averages, not a prediction: the variation between two children of the same age is wide, and the figures below are a landmark, never a target to hit.
Sources
Every figure on this page comes from the references below.
- American Academy of Sleep MedicineRecommended sleep durations, 4 months – 18 years (2016 consensus, endorsed by the American Academy of Pediatrics)
- Réseau Morphée · baby sleepCycles of 50 to 70 min, a night of about 12 h at 1 year, how naps spread from 0 to 3 years
- Réseau Morphée · child sleepCycles of 75 min around 2–3 years, 90 min around 4–5 years, 6 to 7 cycles a night by 5 years
- mpedia · French Association of Ambulatory PaediatricsA cycle of about 50 min from 0 to 2 months, then about 60 min from 2 to 6 months
- Assurance Maladie · ameli.frChild sleep: its stages, its length and its disorders
- Institut National du Sommeil et de la VigilanceChild sleep: needs, and the awakenings between cycles
Work out tonight’s cycle ends
The table above gives the durations; the app applies them to your evening. Enter the child’s age and the time they fell asleep, and the “Sleep cycles” tool lays out the time each cycle ends, flagging the ones where waking up for good becomes likely.
- The time every cycle ends, counted from when they fell asleep
- The end-of-night cycles, where a real waking becomes likely
- The same reference table, available offline
Start your first countdown tonight
Available on iPhone, iPad and Android. An event takes less than a minute to create, and the first "how many sleeps?" gets asked at bedtime.