Many pet owners feed a mix of wet and dry food — perhaps dry kibble in the morning and a portion of wet food in the evening. It's a great approach for palatability, hydration, and nutritional variety. But how do you calculate the right amounts so you're not accidentally overfeeding or underfeeding?
The answer is simpler than it might seem: it's all about calories, not volume or weight.
Step 1: Know Your Pet's Daily Calorie Target (MER)
Before you can calculate portions, you need to know your pet's Maintenance Energy Requirement (MER). Use our calculator for a personalized number, or refer to the reference tables in our dog feeding guide or cat feeding guide.
For this guide we'll use a worked example: a 20 lb (9.1 kg) neutered adult dog with a MER of approximately 602 kcal/day.
Step 2: Find the Caloric Density of Each Food
Every complete-and-balanced commercial pet food in the US must list caloric content on the label under "Calorie Content." This is expressed as kcal per cup (dry) or kcal per can / per 100g (wet).
Typical values (these vary — always use your actual label):
| Food Type | Typical Range | Common Default |
|---|---|---|
| Dry kibble (dogs) | 280–550 kcal/cup | ~350 kcal/cup |
| Dry kibble (cats) | 280–520 kcal/cup | ~350 kcal/cup |
| Wet/canned (3 oz / 85g can) | 60–110 kcal | ~90 kcal |
| Wet/canned (5.5 oz / 156g can) | 120–200 kcal | ~150 kcal |
| Raw/fresh (per cup / 8 oz) | 300–550 kcal | ~450 kcal |
Step 3: The Blended-Diet Formula
When feeding both wet and dry food, decide what percentage of daily calories will come from each source, then calculate the portion size for each separately.
Formula:
Wet food portion = (MER × wet %) ÷ kcal per can
Dry food portion = (MER × dry %) ÷ kcal per cup
Worked Example
Our 20 lb dog needs 602 kcal/day. We want to split 50% wet, 50% dry. Our wet food is 90 kcal per 3-oz can, and our dry is 350 kcal/cup.
- Wet: (602 × 0.5) ÷ 90 = 3.3 cans per day
- Dry: (602 × 0.5) ÷ 350 = 0.86 cups per day
Spread across 2 meals: 1.7 cans + 0.43 cups per meal. If that many cans seems like a lot, consider shifting to 25% wet / 75% dry, which would be 1.7 cans + 1.3 cups per day.
Common Split Ratios
| Ratio | When It Works Well |
|---|---|
| 100% Dry | Budget-focused; dogs/cats who drink plenty of water |
| 25% Wet / 75% Dry | Good balance of hydration, palatability, and cost |
| 50% Wet / 50% Dry | Strongly recommended for cats; good for picky eaters |
| 75% Wet / 25% Dry | Ideal for cats with urinary issues or chronic dehydration |
| 100% Wet | Best for cats with kidney disease or urinary conditions |
Wet vs Dry: Nutrition Comparison
| Factor | Dry Kibble | Wet / Canned |
|---|---|---|
| Moisture content | ~8–12% | ~70–82% |
| Caloric density (per gram) | Higher (4–5 kcal/g) | Lower (0.9–1.3 kcal/g) |
| Protein content (dry matter) | Moderate (26–34%) | Higher (42–52%) |
| Carbohydrates | Higher (30–50%) | Lower (2–10%) |
| Hydration benefit | Minimal | High — mimics prey moisture |
| Palatability | Varies | Generally higher |
| Dental benefits | Some (kibble friction) | Minimal |
| Cost per calorie | Lower | Higher |
| Shelf life (open) | 6–8 weeks (sealed) | 3–5 days (refrigerated) |
Key Takeaways
- Always base portion size on calories, not volume or weight
- Check the "Calorie Content" section of your food label — don't assume a standard value
- When mixing wet and dry, calculate each portion from the same daily calorie budget
- For cats especially, prioritizing wet food is a significant health benefit for hydration and urinary health
- Adjust portions based on your pet's body condition monthly, not just at vet visits
Calculate Your Pet's Mixed-Diet Portions
Select "Mixed (Dry + Wet)" in the food type field for a tailored estimate.
🐾 Use the Free CalculatorFrequently Asked Questions
Is wet food or dry food better for dogs?
Both complete-and-balanced wet and dry foods can meet a dog's nutritional needs. Dry kibble is lower cost per calorie and may offer mild dental friction benefits. Wet food provides significantly more moisture and is often more palatable. A combination of both is a popular and practical choice for most dog owners.
Is wet food or dry food better for cats?
Wet food is generally recommended for cats because cats have a low natural thirst drive and evolved to get most of their hydration from prey (~70% water). Chronic mild dehydration is associated with urinary tract disease and kidney disease — the leading causes of death in domestic cats. Wet food or a wet-heavy combination is preferred by most veterinary nutritionists.
How do I calculate portions when mixing wet and dry food?
Base everything on calories, not volume. Find your pet's daily MER using the calculator. Decide what percentage comes from each food type. Then: wet portion = (MER × wet%) ÷ kcal per can; dry portion = (MER × dry%) ÷ kcal per cup. Always use the actual caloric content from your food label.