The formula
RER = 70 × (body weight in kg)0.75. Daily energy need is RER multiplied by a life-stage factor (Merck Veterinary Manual). The result is a starting point: individual dogs vary by 20% or more. Weigh your Lab every 2–4 weeks and adjust portions by 5–10% to hold a body condition score of 4–5 out of 9.
Treats should stay under about 10% of daily calories, a common veterinary guideline. Puppies and dogs with medical conditions should be fed under veterinary guidance.