* Using a tape measure. Wrap the tape measure around the dog's neck, being careful not to pull it too tight. Make a note of the measurement. Then, wrap the tape measure around the dog's body at its waist, again without pulling it too tight. Add the two measurements together to get the total length of the dog.
* Using a yardstick. Stand the dog against a wall and use the yardstick to measure the distance from the ground to the top of the dog's head. Then, use the yardstick to measure the distance from the nose to the base of the tail. Add the two measurements together to get the total length of the dog.
* Using your arm. Hold your arm out straight with your palm facing up. Stand the dog next to your arm and use your hand to mark the spot where the dog's nose is. Then, use your other hand to mark the spot where the dog's tail base is. Measure the distance between the two marks using your ruler.