Free Pet Calculators
15 pet tools for dogs, cats, and aquariums. Fast, accurate, and completely free.
Quick Answer â Dog Age in Human Years
A 1-year-old dog = ~15 human years. A 2-year-old = ~24. After that, add 4-5 years per dog year (varies by size â larger breeds age faster).
A 7-year-old medium dog is roughly 47 in human years. See the full conversion table below, or get an exact result with our calculator.
Daily dog food: ~2-3% of body weight for adults. A 30 lb (14 kg) dog needs roughly 350-400 calories/day. Cat food: ~200-300 calories/day for an average 10 lb cat.
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Dog Age Conversion Chart â Quick Reference
| Dog Age | Small (<20 lb) | Medium (20-50 lb) | Large (50-90 lb) | Giant (90+ lb) |
|---|---|---|---|---|
| 1 year | 15 | 15 | 15 | 12 |
| 2 years | 24 | 24 | 24 | 22 |
| 3 years | 28 | 28 | 28 | 31 |
| 5 years | 36 | 36 | 40 | 49 |
| 7 years | 44 | 47 | 56 | 67 |
| 10 years | 56 | 60 | 72 | 85 |
| 13 years | 68 | 74 | 88 | 100+ |
Values in human years. Based on AKC veterinary aging guidelines. Get exact results for your dog →
About PetCalc
PetCalc provides 15 free online pet calculator tools for dog owners, cat owners, and aquarium hobbyists. All calculations run instantly in your browser â no data is sent to any server.
Why Use PetCalc?
- Accurate: Formulas based on veterinary guidelines (AKC, RER)
- 15 Tools: Dog, cat, and aquarium calculators in one place
- Instant Results: Calculations happen as you type
- Free: No registration, no fees, unlimited use
- Mobile-Friendly: Works on any device
What Are Pet Calculators?
Pet calculators are specialized online tools that help pet owners make informed decisions about their animals' health, nutrition, and environment. Rather than guessing how much food your dog needs or whether your aquarium can handle another fish, these calculators apply veterinary-backed formulas to give you precise, science-based answers in seconds.
The most popular pet calculator is the dog age converter, which translates a dog's chronological age into "human years." While the old rule of thumb was simply multiplying by 7, modern veterinary science uses a logarithmic scale that accounts for the fact that dogs mature rapidly in their first two years and then age more slowly. A 2-year-old dog is roughly equivalent to a 42-year-old human, not 14. Our calculator uses breed-specific size categories â small, medium, large, and giant â because larger breeds age faster than smaller ones after the initial growth phase.
For aquarium hobbyists, stocking calculators solve one of the most common beginner mistakes: overstocking a tank. The general guideline of "one inch of fish per gallon" is a starting point, but actual bioload depends on the species' activity level, waste production, and territorial needs. Our fish stocking calculator factors in tank dimensions, filtration capacity, and species compatibility to give a more realistic recommendation.
Frequently Asked Questions
How accurate is the dog age calculator?
The dog age calculator uses the American Kennel Club's updated age conversion formula, which accounts for breed size (small, medium, large, giant). It is significantly more accurate than the old "multiply by 7" rule, reflecting the fact that dogs mature rapidly in year one and two, then age more gradually. Results align with current veterinary aging guidelines.
How much food should I feed my dog per day?
Daily food requirements depend on your dog's weight, age, activity level, and whether the food is dry kibble or wet. The general guideline is based on Resting Energy Requirement (RER): RER = 70 x (body weight in kg)^0.75 calories per day, then multiplied by a life-stage factor (1.6 for active adults, 1.2 for senior dogs). Our dog food calculator handles all of this automatically when you enter your dog's details.
How do I calculate my cat's age in human years?
A cat's first year equals approximately 15 human years, and the second year adds about 9 more, bringing a 2-year-old cat to roughly 24 human years. After that, each additional cat year equals about 4 human years. So a 5-year-old cat is approximately 36 in human terms. Our cat age calculator applies this piecewise formula automatically.
How many fish can I put in my aquarium?
The basic rule is 1 inch of fish per gallon of water, but this varies greatly by species. Active swimmers need more space, while bottom-dwellers share different territory. A 20-gallon tank might hold 10-12 small tetras but only 2-3 larger cichlids. Our fish stocking calculator considers tank volume, filtration type, and species bioload for a more reliable estimate.
Is PetCalc really free?
Yes, every calculator on PetCalc is completely free with no registration, no hidden fees, and unlimited use. All calculations run directly in your browser â no personal data is collected or stored on any server.