Pet Nutrition & Care Calculation Guide
Daily food calories for dogs and cats, aquarium volume, and equine forage needs.
Responsible animal stewardship requires appropriate nutrition and environment sizing. Calculating your pet's daily resting energy requirement (RER), proper aquarium filtration turnover, and equine forage needs prevents obesity and ensures long, healthy lives.
Life stage multipliers: Neutered adult dog = 1.6, Intact dog = 1.8, Weight loss = 1.0, Senior = 1.4, Neutered cat = 1.2.
Scenario: Calculating daily maintenance calories for a neutered adult dog weighing 20 kg.
- Weight: 20 kg
- Multiplier: 1.6 (neutered adult)
- Weight^0.75 = 20^0.75 ≈ 9.457
- RER = 70 × 9.457 = 662 kcal/day
- Maintenance Calories = 662 × 1.6 = 1,059 kcal/day
- Treats should never exceed 10% of a dog or cat's total daily caloric allowance.
- Equine forage: horses require 1.5% to 2.5% of their body weight in dry hay daily to maintain gut motility.
- Aquarium sizing: 1 US gallon of fresh water weighs approximately 8.34 lbs (3.78 kg); ensure furniture supports the total filled aquarium weight.
- Aquarium filtration turnover should cycle the entire water volume at least 4 to 6 times per hour.
Put the formulas above into practice with these free tools:
Dog Daily Calorie Calculator
Daily calories and cups of food for a dog by weight and life stage.
Cat Daily Calorie Calculator
Daily calories and cups of food for a cat by weight and life stage.
Pet Food Cost Calculator
Daily, monthly, and yearly food cost plus how long a bag lasts.
Pet Weight Loss Timeline Calculator
How many weeks a pet needs to reach its target weight at a safe weekly pace.
Puppy Adult Weight Calculator
Estimate how much a puppy will weigh when fully grown.
Cat Age in Human Years Calculator
Convert your cat's age to human years and see its life stage.
Pet Daily Water Intake Calculator
How much water a dog or cat needs each day by weight.
Aquarium Volume Calculator
Water volume of a rectangular tank in liters and gallons.
Aquarium Stocking Calculator
Rough number of small fish a tank can hold using the inch-per-gallon rule.
Aquarium Water Change Calculator
How much water to replace to bring nitrate down to your target.
Aquarium Heater Size Calculator
Heater wattage needed to warm a tank from room temperature.
Aquarium Treatment Dose Calculator
Scale a water conditioner or medication dose to your tank volume.
Is one human year really equal to seven dog years?
No; dogs mature rapidly in their first two years (a 1-year-old dog equals roughly a 15-year-old human), after which aging slows to roughly 4 to 5 human years per calendar year depending on breed size.
How do you calculate aquarium water volume?
Multiply length × width × height in inches, then divide by 231 to obtain US gallons.
How do I adjust feeding for an overweight pet?
Calculate calories based on target ideal body weight rather than current overweight measurement, using an RER multiplier of 1.0.