About CritterCalcs
CritterCalcs provides free, vet-reviewed calculator tools for dog and cat owners. Every tool on this site is built on a published veterinary or nutrition formula, tested against known values from that source, and — where it carries clinical or nutritional claims — reviewed by a qualified veterinary or nutrition expert before publication. The site currently offers 56 tools covering medication dosing, toxicity assessment, nutrition, growth prediction, weight management, vaccination scheduling, and more.
CritterCalcs grew out of CalculatorCorp.com, a 4,300+ page calculator platform that has served hundreds of thousands of calculations across multiple domains over several years. After building precision tools for printing, construction, electrical engineering, and general use, the pet health space stood out: the gap between professional veterinary knowledge and what pet owners can actually access online is significant. Most pet calculators available are basic, unsourced, and clinically unreviewed. CritterCalcs was built to bridge that gap with purpose-built tools backed by published veterinary science and independent expert review.
Who builds the tools
Dan Dadovic builds and maintains the calculator tools on CritterCalcs. He is a Commercial Director at Ezoic, an ad monetisation platform for digital publishers, and a PhD candidate in IT Sciences, based in Northumberland, UK.
Dan built CalculatorCorp.com and operates a portfolio of niche-specific calculator sites: PrinterTools, HardHatCalc, VoltCalcs, and PeakCalcs. Across these platforms, he has developed over 4,300 precision calculator tools. CritterCalcs applies that same methodology — structured data validation, automated testing, and formula verification — to the pet health domain.
Dan is not a veterinarian. His role is explicit: he builds the tools, implements the formulas from published veterinary sources, and ensures every calculation is testable and traceable to its cited reference. Every clinical element on this site — medication dosages, toxicity thresholds, severity classifications, and health recommendations — is reviewed by a qualified, practising vet before publication. This separation between tool builder and subject-matter reviewer is deliberate. The tools are engineered by someone with deep experience in calculator development; clinical and nutritional accuracy are each verified by a reviewer qualified to assess them.
Who reviews the content
CritterCalcs content is reviewed by two independent subject-matter experts: a practising veterinary surgeon for clinical, toxicity, and medication content, and a veterinary nutrition academic for feeding and dietetics content. Full reviewer bios, credentials, and assigned scopes live on the editorial reviewers page.
How we work together
The development process separates tool engineering from subject-matter review. Dan identifies the published veterinary formula — from sources such as Plumb's Veterinary Drug Handbook, the BSAVA Small Animal Formulary, the Merck Veterinary Manual, ASPCA Animal Poison Control Center data, WSAVA Global Nutrition Committee guidelines, WALTHAM Petcare Science Institute growth studies, and AKC or CFA breed standards — and implements it in code with automated tests that verify the calculation against known values from the source.
Ivana then reviews every clinical element: dosage ranges, toxicity thresholds, severity band cutoffs, health recommendations, contraindications, and the educational content presented alongside calculator results. This is not a rubber stamp. Cat medication dosing, for example, requires feline-specific protocols because cats lack the glucuronidation pathways that dogs use to metabolise certain drugs — a generic “pet” calculator using dog dose ranges could recommend a dose that is toxic to cats. Species-specific risks like this are precisely what clinical review catches.
Feeding content follows the same separation under a different reviewer. Prof. Tomislav Mašek, PhD, a professor of animal nutrition and dietetics at the University of Zagreb Faculty of Veterinary Medicine, reviews the calorie mathematics and portioning logic behind the food, growth-stage feeding, and raw-feeding tools, confirming that the recommendations reflect current animal-nutrition science. He is not a veterinary clinician — medication, toxicity, and dosing content stays with the clinical reviewer.
Clinically reviewed pages display “Reviewed by Ivana Pintar, MRCVS” with her RCVS registration number; nutrition-reviewed pages display “Reviewed by Prof. Tomislav Mašek, PhD”. Each page carries a single reviewer, chosen by its primary subject. Pages requiring clinical sign-off are flagged in the content system and cannot be published without it — this includes all medication dosage calculators, toxicity assessment tools, vaccination schedulers, and weight management tools.
What this site cannot do
CritterCalcs provides general guidance tools based on published veterinary protocols. It is not a substitute for a veterinary examination.
If your pet is showing symptoms of illness, contact your vet directly. The toxicity calculators provide an urgency assessment to help you decide how quickly to act — they do not provide a diagnosis.
Medication dosages should always be confirmed with your treating veterinarian before administration. Individual factors including kidney function, age, concurrent medications, and body composition affect appropriate dosing in ways that a calculator cannot account for.
Individual animals vary even within the same breed and weight. A 35 kg Labrador and a 35 kg Staffordshire Bull Terrier may need different approaches. These tools provide evidence-based starting points; your vet knows your individual pet.
Contact
For questions, corrections, or feedback about CritterCalcs, email hello@crittercalcs.com. Corrections to medical or scientific content are prioritised and reviewed within 48 hours.
For a detailed explanation of the development process, data sources, and testing methodology, see the methodology page. For data subject requests under GDPR, see the privacy policy.