How old is your pet, really?
35 free calculators, all on real veterinary sources (NRC, WSAVA, AAHA). Try one now — your dog's real age in human years in five seconds.
- Small · <20 lb
- Medium · 20–50 lb
- Large · 50–90 lb
- Giant · 90+ lb
Got a cat? Try the cat age calculator →
All 35 calculators & guides
Free, neutral, evidence-based. Built by one person · Methodology never tilted by sponsor money.
Compare a dog and a cat
Is your cat older than your dog in human terms? Both ages converted side by side, with life stages.
OpenDog age calculator
Real dog years to human years, size-based, with breed lifespan context.
OpenCat age calculator
Cat years to human years, indoor vs outdoor lifespan adjusted.
OpenChocolate toxicity (dogs)
My dog ate chocolate — how dangerous? Vet-referenced severity bands + hotline numbers.
Grape toxicity (dogs)
Acute kidney injury risk. Any ingestion warrants a hotline call.
Raisin toxicity (dogs)
Concentrated-grape dose math + severity bands.
Xylitol toxicity (dogs)
Sugar-free gum + peanut-butter exposures. Fastest-acting common toxin.
Ibuprofen toxicity (dogs)
Advil + Motrin dose math by weight + tablet strength. Severity bands + ER thresholds.
Mushroom poisoning (dogs)
Which wild mushrooms are dangerous, the symptom patterns they cause, and what to do first.
Marijuana / THC toxicity (dogs)
THC dose math by product type (flower, edible, oil, concentrate), and what to tell the vet.
Cat + Tylenol emergency
Cats cannot safely metabolise acetaminophen. Any amount is an emergency — call a vet or poison line now.
Cat + grape toxicity
Less-studied than dog-grape but treat any exposure as precautionary. Mechanism conserved across species.
Cat + essential oils
All essential oils are toxic to cats — they lack the liver enzyme to metabolize them. Diffusers included.
German Shepherd lifespan deep-dive
9-13 years average. Working vs show line difference, OFA hip screening, DM genotyping.
Golden Retriever lifespan + cancer data
Typical lifespan, why cancer dominates Golden health data, and what owners can actually influence.
French Bulldog lifespan + BOAS
10-12 years. BOAS, heat management and the health issues the published studies flag.
Dog pregnancy / gestation
63-day timeline with prenatal milestones.
Dog poop color guide
Interactive: pick color + consistency, see vet urgency.
Daily calorie needs (dogs)
NRC-based RER × MER. Life-stage, activity, and neuter-adjusted.
Calorie deficit (weight loss)
Daily target for a safe, sustainable weight-loss plan.
Raw food amount
PMR / BARF daily grams, with muscle / organ / bone breakdown.
Puppy growth
How big will my puppy get? Size-band growth curves + milestones.
Crate size guide
Right crate size by adult weight + optional body measurements.
Compare two dogs
Side-by-side human ages, life stages, and a plain-English summary.
Compare breeds
Two dog or cat breeds side-by-side: lifespan, size, health, cost, grooming.
Daily calorie needs (cats)
Cat-tuned multipliers + a safer weight-loss plan (hepatic lipidosis aware).
Cat pregnancy / gestation
62-day queen timeline with prenatal milestones + eclampsia signs.
Litter box count (cats)
The n+1 rule: how many boxes for your household + where to put them.
Cat litter cost
Estimate monthly + annual litter spend across litter types.
Ideal weight (dog & cat)
Visual BCS picker back-calculates the target weight and time to reach it.
Senior pet wellness tracker
Log weight + appetite + mobility over time. Stored in your browser only.
Food safety — can pets eat this?
Searchable safe / caution / toxic list for 50+ human foods.
Flea & tick prevention guide
Collar vs topical vs oral — honest trade-offs and FDA adverse-event data.
Dewormer guide
Which worm, which drug. OTC vs prescription, puppy/kitten schedule.
Wet vs dry food split
How much wet + dry per day for a target mix and calorie target.
Treat allowance
The AAHA 10% rule with a database of common treats and what fits.
Water intake
Daily water needs split into "from food" vs "from the bowl".
Lifetime cost of ownership
Food + vet + grooming + supplies + insurance over a full lifespan.
No calculators match that species yet. .
Five breeds, written up in depth
Individually researched pages on lifespan, the health problems each breed is known for, and the sources behind the numbers. For any other breed, the dog age and cat age calculators handle the conversion by size and lifestyle.
- Labrador Retriever age & lifespan · Weight, joints, and the Purina lifetime study
- Golden Retriever lifespan · Cancer risk and what owners can influence
- German Shepherd lifespan · Working vs show lines, hips, and DM
- French Bulldog lifespan + BOAS · Breathing, heat management, VetCompass data
- Ragdoll lifespan · How long Ragdolls live and what shortens it
Dog ages at a glance
Same chronological age, very different human-equivalent age — that's the AKC size-based method in action.
Daily calorie needs — RER × 1.2 / 1.6 / 2.0
NRC 2006 method: resting energy requirement (RER) times a life-stage and activity multiplier. Adjust for age, neuter status and activity in the full calculator.
| Body weight | RER × 1.2 · inactive / senior | RER × 1.6 · typical neutered adult | RER × 2.0 · very active / working |
|---|---|---|---|
| 5 lb (2.3 kg) | 157 kcal | 209 kcal | 261 kcal |
| 15 lb (6.8 kg) | 354 kcal | 472 kcal | 590 kcal |
| 30 lb (13.6 kg) | 595 kcal | 793 kcal | 991 kcal |
| 50 lb (22.7 kg) | 874 kcal | 1165 kcal | 1456 kcal |
| 75 lb (34.0 kg) | 1183 kcal | 1577 kcal | 1971 kcal |
| 100 lb (45.4 kg) | 1469 kcal | 1959 kcal | 2449 kcal |
Numbers are kcal per day. Underlying formula: RER = 70 × (kg0.75), then daily need = RER × multiplier. Typical multipliers, each applied directly to RER (not to the columns above): neutered adult about 1.6×, intact adult about 1.8×, puppy under 4 months about 3.0×, puppy 4–12 months about 2.0×, inactive or senior dog about 1.2–1.4×. These are starting points — adjust by body condition, and use the calculator for puppies and weight-loss plans.
Made by Carl and Mochi
Hi, I'm Carl. Goodboy Atlas started because every time I tried to answer a simple numerical question about Mochi — a mixed-breed rescue — I'd land on either a food-brand calculator quietly pushing kibble, a generic listicle with no sources, or a 2019 Reddit thread written by someone with no veterinary background.
So I built the site I wished existed: every calculator shows its method and cites a published source, and I'm not a veterinarian, so the pages say where the honest answer is "ask your vet". The site is intended to be funded by display advertising only — no affiliate links, no sponsored placements, no food-brand money.
Why we built this
Pet calculators online are usually either branded marketing tools (designed to funnel you toward a specific food brand) or buried single-purpose pages on huge general sites. We wanted one neutral place that does the math carefully and explains where each number comes from.
Every calculator on Goodboy Atlas shows two things on the same page: the result, and the method we used to get there. If you disagree with our assumptions, change them. If you want to read the underlying source, the citations are at the bottom of every page.
Today the site has 35 calculators and guides, plus five individually written breed pages. Every page is written and maintained by one person from published veterinary sources — NRC, AAHA, WSAVA, AAFP, and the poison-control services' published dose data — and lists the sources it uses. When a reader or a newer source shows a figure is wrong, the page is corrected and the change is recorded in the changelog. How sources are chosen and corrections are handled is set out in the editorial policy.
Page last updated .