Guess your puppy's adult weight

At eight weeks of age

Multiply the pup's weight by 4. If the number comes out greater than 20kg, add 5 to 7 kg. If the number comes out greater than 35kg, add 7 to 10kg.

At twelve weeks of age

Multiply the pup's weight by 3. Follow the above rules if it comes out greater than 20kg or 35kg.

At sixteen weeks of age

Multiply the pup's weight by 2. Follow the above rules if it comes out greater than 20kg or 35kg.

To be more precise, average the three weights you get at the different ages.