Crib hour
Also called crib-hour, the crib hour, crib 90, crib 120
Crib hour is a nap rule where a baby who wakes early from a nap stays in the crib until a full hour has passed, in the hope they drift back to sleep. Some families count the hour from the moment the baby was put down and others from when they fell asleep.
How it's said
Crib hour: have you heard of it? I've heard this called many things, but crib hour has definitely been the most understood.
When a child is on one nap, some parents will practice "crib 90" or "crib 120"...
...here's why I don't subscribe to crib hour.
Who says it
Where it came from
Crib hour is a young name. A sleep consultant writing in 2021 called it a newer term that doesn't show up in PubMed, and said the first question parents ask is whether it means leaving the baby to cry for the rest of the hour.
The idea is older than the name. Alexis Dubief's Precious Little Sleep guide to short naps sets naptime at one hour and leaves a baby who wakes early in the crib until the hour is up. Consultants now write whole posts on it, and some describe parents of a one-nap child stretching it to crib 90 or crib 120. A 2025 sleep podcast ran an episode on why its host isn't a fan.