An adult dog will usually sleep between eight and fourteen hours a day, but there’s a wide gap between the two figures to allow for lots of range.
The number of hours of sleep a dog need can depend on several different things. Age, size, health, and breed are all factors that need to be considered. Not only that, but individual preference can also mean slight differences. Even with humans, you could have an identical twin who prefers to sleep in more than you just like two Labradors may have different sleep schedules.
Activity levels and lifestyle, even the environment can all be considered when considering how long dogs sleep. Health issues such as diabetes, kidney issues, hypothyroidism, and arthritis can all make a dog need more sleep, so it really depends on so many different factors.