Adults: 

There is no set rule, but for an adult dog roughly 2-3% of their body weight in food every day should suffice. In other words, a 10kg dog should be eating around 200-300g.

If you have an underweight or very active dog, increase this to between 3% and 5% of body weight a day.

For elderly or overweight dogs reduce the intake to between 1% and 2% of body weight per day.

Puppies: 

For puppies under 4 months feed around 5% of their body weight per day. For puppies 5-12 months feed around 3% of the breed’s average adult body weight per day i.e. you are starting to feed them as if they are fully grown.

Remember that each dog is an individual - their breed, size, age and activity level will affect their overall nutritional requirements.

When you switch to any new food, you should monitor the quantity you serve and make adjustments accordingly.