Usually it's one hour per pound of body weight, I know this to be true in puppies. Once a dog matures, I'm sure it can hold it's bladder longer. I wouldn't let a dog go without going outside over 5 hours, though.. adult or not. If you do, you surely can't be upset with the dog relieving itself in the house.
You both have confused me. LOL!! So my dog is 4 yrs. old. That is 48 months. That can't be right. Or do you stop at 12 months and then add 1 hour to that? I asked a vet on another forum. She said dogs do not process urine like humans and can hold it much longer than we can. She said it should be dark yellow in color. She said for me not to dally when getting home and letting him out but he should be able to hold it for 8 hours. I have found spots where he has wet though.......so??????? Oh and btw, I am not upset at him for having accidents. This is an argument between my husband and I. That is why I am asking.
Since your dog is a small breed, he has a smaller bladder. If he has access to all the water he can drink (as he should have) I would not expect him to hold it for 8 hours. I think 4-6 is plenty long enough.
Are you concerned about how long it is okay to leave the dog alone? Or are you concerned that there is a medical problem? Most of my small dogs have had to go more frequently than larger breeds, so I had to get up in the middle of the night sometimes. But I had one dog, that held it for almost 48 hours! He was terrified of the storms we were having and refused to go outside, and he never, ever had an accident inside, I felt bad for the poor guy, and finally drug him outside in the rain until he went.
"Since your dog is a small breed, he has a smaller bladder"
Yes, he has a smaller bladder, but he also drinks less. I just don't get the smaller bladder thing. It's not like a chihuahua drinks a great dane amount of water and can't hold it-he drinks a chihuahua amount of water!
And yes, the hours just applies to puppies, obviously. Otherwise, a 7 year old dog could hold it for about a week!
A four year old dog should be able to 'hold it' for around eight hours under normal circumstances. Sometimes certain medications or heat can increase thirst which may affect his usual habits. Also increased urination can be a sign of infection or another condition. Some dogs may even react adversly to disturbances and urinate from anxiety when alone. Just a thought.
I think it depends on the dog. At 5 months old my Mini dachshund could hold it all night. As long as I took her out right before bed and right when she got up and limited her water intake before bedtime.
Notice I said this is usually a rule of thumb in puppies.. lol. I never mentioned a 40lb dog. :p My vet told me, a 3lb puppy should be able to hold it for three hours. Duchess is 6lbs and can hold it every bit as good. I've also heard the year of age thing, too. but what about a dog that's 17 years old.. can it hold it that long? It's all up for debate. The fact is, a dog.. no matter the age, or weight.. should be let outside to relieve itself at least once every 3 hours.