Dog Nutrition Calculator
Calculate dog nutrition with our free science calculator. Uses standard scientific formulas with unit conversions and explanations.
Formula
RER = 70 x (Weight in kg)^0.75 | MER = RER x Activity Factor x Life Stage Factor x Condition Factor
Resting Energy Requirement (RER) represents basal metabolic needs calculated using metabolic body weight. Maintenance Energy Requirement (MER) adjusts RER by activity level (1.2-2.5x), life stage (0.8x for seniors, 2-3x for puppies), and body condition (0.7x for obese to 1.2x for underweight). Macronutrients are calculated as percentages of total calories following AAFCO guidelines.
Frequently Asked Questions
How many calories does my dog need per day?
A dog daily caloric needs are calculated using the Resting Energy Requirement (RER) formula: 70 x (body weight in kg)^0.75. This base metabolic rate is then multiplied by factors for activity level and life stage. A sedentary 20-lb dog needs about 340 calories/day, while an active working dog of the same weight might need 850 calories/day. Puppies require 2-3 times the adult calories per kg for growth. Senior dogs typically need 20% fewer calories as their metabolism slows. These are starting points; adjust based on whether your dog is gaining or losing weight.
What is the ideal protein-to-fat ratio for dog food?
For adult dogs, AAFCO recommends minimum 18% protein and 5% fat on a dry matter basis, but most nutritionists recommend higher amounts: 25-30% protein and 12-18% fat for optimal health. Active and working dogs benefit from higher fat content (20-30%) for sustained energy. Puppies need at least 22% protein and 8% fat to support growth. Senior dogs may benefit from higher protein (28%+) to maintain muscle mass, but with moderate fat to prevent weight gain. The remaining calories come from carbohydrates, which while not essential for dogs, provide fiber, vitamins, and readily available energy.
How much water should my dog drink daily?
The general guideline is that dogs should drink approximately 50-60 ml of water per kilogram of body weight per day, or roughly 1 ounce per pound. A 50-lb dog needs about 50 ounces (6+ cups) daily. Water needs increase significantly with exercise, hot weather, dry food diets (which contain only 10% moisture vs. 78% in wet food), pregnancy, lactation, and illness. Signs of dehydration include dry gums, loss of skin elasticity, lethargy, and sunken eyes. Always ensure fresh, clean water is available. Some dogs prefer running water from fountains, which can encourage greater fluid intake.
How often should I feed my dog?
Feeding frequency depends on age and life stage. Puppies under 4 months need 4 meals per day as their small stomachs cannot hold enough food in fewer meals. From 4-12 months, 3 meals per day is appropriate. Most adult dogs do well on 2 meals per day, spaced approximately 12 hours apart. Senior dogs may benefit from 2-3 smaller meals to aid digestion. Lactating mothers may need free-choice feeding or 3-4 meals to meet their extraordinary energy demands. Avoid feeding one large meal per day, especially for large breeds, as this can increase the risk of bloat (gastric dilatation-volvulus), a life-threatening emergency.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
Can I share or bookmark my calculation?
You can bookmark the calculator page in your browser. Many calculators also display a shareable result summary you can copy. The page URL stays the same so returning to it will bring you back to the same tool.