This seems to be a very common problem in puppies, but unfortunately it can be a real problem with older dogs as well. Not good if your adult dog weighs 40kg!
Prevention is better than cure. If you have a new pup or dog make sure you set the rules straight away. And this means making sure all family members comply. Sometimes it’s not the 4 legged family member that is the problem; it’s often the smaller 2 legged variety!
Jumping up is not abnormal, it’s just unacceptable. Your dog or puppy is going to get excited and playful, and when seeking out your attention or playing, your dog is likely to jump up at times. How you deal with this behaviour will affect the dogs’ future actions.
Jumping up is attention seeking so if you give attention by pushing the dog down, telling the dog off, giving eye contact or worse still, patting or playing with your dog then you will encourage the behaviour (making it much harder to retrain later on). Adults and children should withdraw all contact and turn away from the dog.
Children (and adults) may find it helps to cross their arms and turn away. Walk away if needed. If you indulge the behaviour and give the dog attention when it is excitable and out of control you may also have the problem of the dog grabbing at clothes and chasing (more on that another time).
Make sure everyone is consistent when dealing with jumping up. If 1 person is not sticking to the training you will have trouble correcting the problem.
Reward for all 4 feet being on the ground & reward calm relaxed behaviour. Teach the dog to sit for attention or upon approach. Outdoor dogs can benefit from time inside as calm behaviour is needed & encouraged when they come indoors. If your dog is not used to being inside bring them in on a lead and get them to settle on their bed or mat.
When visitors arrive put the dog on a lead so you can control the behaviour (keep a spare slip lead by the door) that way your dog won’t have control over the interaction with the visitor and the visitor won’t be able to encourage bad habits such as jumping up.
Jumping up may get worse before it gets better as your dog may try harder to get a response from you. Don’t give up, persistence is the key!