39 free tools · no account · nothing leaves your browser
Dog calculators that show their working
39 free tools for the questions dog owners actually search at 11pm: how much to feed, whether that chocolate is dangerous, how old a dog is in human years, what size crate to buy. Every calculation runs in your browser, nothing you enter is sent anywhere, and every formula is written out on the page with its veterinary source.
- 39
- Calculators, all live
- 29
- “Can dogs eat…?” answers
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- Calculator inputs sent to a server
Dog care tips by email
Get the number before you need it
Short, occasional emails: one feeding, safety or health tip at a time, each with the calculator behind it. No schedule, no spam, unsubscribe in one click.
Stored by DogCalcs, never shared. See the privacy page.
Your dog ate something. Work out the dose now.
Most used
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Dog Calorie CalculatorCalculate how many calories your dog needs per day from body weight, life stage and activity level, using the standard RER and MER veterinary formulas.
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Dog Food Portion CalculatorDog food portion calculator: turn a daily calorie target into grams or cups of the food you buy, from manufacturer-verified kcal/kg figures or your own bag.
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Dog Chocolate Toxicity CalculatorDog chocolate toxicity calculator: the theobromine dose in mg per kg of body weight for what your dog ate, and the symptoms expected at that dose.
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Dog Age Calculator: Dog Years to Human YearsConvert your dog’s age into human years using size-adjusted veterinary life-stage data instead of the inaccurate multiply-by-seven rule.
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Puppy Weight Calculator: Predict Adult SizePredict how big your puppy will grow from its current age and weight, adjusted for expected breed size group.
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Puppy Vaccination Schedule CalculatorGenerate a dated core vaccination timeline from your puppy’s date of birth, including booster and rabies timing.
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Dog Crate Size CalculatorDog crate size calculator: the right crate dimensions from your dog’s length and height, with the standard crate size that fits.
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Dog Daily Water Intake CalculatorDog water intake calculator: how much water your dog should drink each day, and the intake that suggests excessive thirst worth a vet visit.
All 39 calculators, by category
Every tool, one click away
Feeding
How much should a dog eat? Start with daily calories from body weight, life stage and activity, then convert that to grams or cups of the food you actually buy. There are also tools for treat allowances, raw and home-cooked rations, splitting a bag between several dogs, switching foods without an upset stomach, and how much water a dog should drink.
Health
Is my dog a healthy weight, and how old is it really? Convert dog years to human years with size-adjusted tables, score body condition, find an ideal weight and plan safe weight loss, predict a puppy’s adult size, and check whether your dog counts as a senior yet.
Schedules
When is the next vaccine, wormer or flea treatment due? Build dated puppy vaccination and deworming timelines from the AAHA, WSAVA and CAPC guidelines, plan parasite prevention, and work out a due date or the next heat cycle.
Safety
My dog ate something — is it dangerous? Dose calculators for chocolate, grapes and raisins, xylitol, onion and garlic, all worked in mg per kg of body weight against published thresholds, plus a hot pavement checker and a guide to which people foods are safe.
Sizing
What size crate, collar, harness, bed or dog door does my dog need? Sizing from real measurements rather than breed guesses, airline crate rules, and the practical numbers: exercise minutes, potty-break spacing, crate time limits, and what a dog costs to own.
Who is behind this, and how the numbers are checked
DogCalcs is written and maintained by Ashar Islam, a developer, not a veterinarian, which is why the site is built so you do not have to take the author's word for anything.
Each tool starts from a published veterinary formula or dose threshold, shows that formula on the page, and cites the source beside it. The arithmetic lives in separate, unit-tested modules, so a wrong constant fails a build rather than reaching a dog.
Where the science is uncertain — grape toxicity has no established dose, energy needs vary about 20% between similar dogs — the page says so instead of rounding it away. Every tool carries the date it was last read end to end.
None of this replaces a vet. It is meant to get you to the appointment already knowing what to ask, and to tell you when the appointment needs to be right now.
From the blog
- How big will my puppy get? Adult weight by age
How big will my puppy get? Divide current weight by the fraction of adult weight typical for its age and size: a medium puppy at 4 months is about 53% grown.
- How long are dogs pregnant? 63 days, week by week
How long are dogs pregnant? About 63 days from ovulation and remarkably consistent. From the mating date it can look like 57 to 72. Milestones week by week.
- How much xylitol is toxic to a dog?
How much xylitol is toxic to a dog: blood sugar crashes from about 0.1 g per kg; liver damage from 0.5 g/kg. For a 10 kg dog, one or two pieces of gum.
- How often do puppies need to pee? Hold times by age
How often puppies need to pee: a puppy can hold roughly its age in months plus one, in hours. That is a ceiling, not a schedule. When to go out instead.
Common questions
Are these dog calculators free?
Yes, all of them, with no account and no limit. The site is supported by nothing more than being useful; there are no paywalled results and no upsell after the answer.
Where do the formulas come from?
Published veterinary sources: the National Research Council nutrient requirements, WSAVA and AAHA guidelines, the Merck Veterinary Manual, poison control centers and peer-reviewed papers. Every tool prints the formula it used and cites the source directly under it, and the full list is on the sources page.
Can a calculator replace my vet?
No. A calculator applies a population formula to one dog. It is a starting point for a feeding plan or a reason to phone a vet now, not a diagnosis. The toxicity tools in particular tell you when to call; they cannot tell you your dog is safe.
Is anything I type sent anywhere?
No. Every calculation runs in your browser. The site has no server-side code and no form that transmits what you enter. Cookieless page-view analytics is the only measurement, and it never sees the numbers you type.
How often are the numbers checked?
Every tool shows the date it was last reviewed end to end in its byline. The current site-wide review date is September 13, 2026, and individual tools carry their own date when a formula, constant or claim on that page has changed since.
Why do the results differ from the feeding guide on my dog food bag?
Bag charts are keyed to body weight alone and have to cover the hungriest dog in each row, so they usually run generous. The calorie calculator also uses life stage, neuter status and activity level. A gap of 10 to 15% is expected; your dog’s body condition over the next month settles which is right.