Methodology & Editorial Policy

Last updated: 4 April 2026

CritterCalcs exists to make published veterinary science accessible to pet owners through accurate, tested calculator tools. This page explains how we build our calculators, where our data comes from, and the review processes we follow before publishing any tool.

How calculators are built

Each calculator follows a structured development process designed to ensure accuracy at every stage:

1. Source identification: We identify the published veterinary formula, protocol, or guideline that will power the calculator. This must be a peer-reviewed source, established veterinary reference, or data from a recognised veterinary institution.
2. Formula implementation: The formula is implemented in code and tested against known values from the source material. Every calculator function includes test cases with inputs and expected outputs drawn directly from the published source.
3. Worked example verification: Each calculator includes at least two worked examples with realistic scenarios. The inputs from every worked example are run through the actual calculator code, and all intermediate and final values are verified to match the narrative.
4. Clinical review: Medical, toxicity, and health calculators are reviewed by a practising veterinarian who verifies formula accuracy, dosage ranges, contraindications, warnings, and the educational content presented alongside results.
5. Publication: Only after passing automated tests and clinical review (where required) is a calculator published to the live site.

Our data sources

Medication dosages

Medication dose ranges are sourced from established veterinary formularies, primarily:

• Plumb's Veterinary Drug Handbook — the standard North American veterinary drug reference
• BSAVA Small Animal Formulary — the standard UK veterinary drug reference published by the British Small Animal Veterinary Association

Where these sources differ, we note the variation and typically present the range that covers both recommendations. Every medication entry cites its specific source.

Toxicity thresholds

Toxicity threshold values (the doses at which mild, moderate, severe, and lethal symptoms are expected) are sourced from:

• Merck Veterinary Manual — a comprehensive veterinary reference covering toxicology, pathology, and clinical medicine
• ASPCA Animal Poison Control Center — the leading animal poison control resource in North America, with published data on common pet toxins

Theobromine concentrations for chocolate types (dark, milk, white, cocoa powder, baking chocolate) are based on published analytical data referenced in the Merck Veterinary Manual.

Breed data

The breed database is compiled from official kennel club standards and published veterinary research:

• American Kennel Club (AKC) — breed standards for 200+ recognised dog breeds, including weight ranges, height ranges, and general characteristics
• The Kennel Club (KC) — UK breed standards where AKC data is unavailable or differs significantly
• Cat Fanciers' Association (CFA) and The International Cat Association (TICA) — breed profiles for 50+ recognised cat breeds
• WALTHAM Petcare Science Institute — growth curve data from published peer-reviewed studies on puppy and kitten development

Nutrition formulas

Nutritional calculations (resting energy requirement, maintenance energy requirement, food portions) use standard veterinary nutrition formulas as published in veterinary nutrition textbooks and WSAVA (World Small Animal Veterinary Association) guidelines. The specific formula is cited on each calculator page.

Veterinary review process

Pages flagged as requiring veterinary review (all medication, toxicity, and health calculators) undergo clinical review by a practising veterinarian. The review covers:

• Formula accuracy against cited source
• Dosage range appropriateness for the target species
• Contraindications and warnings completeness
• Drug interaction and species-specific metabolism notes
• Toxicity threshold accuracy
• Educational content clinical accuracy
• Appropriate caveats and disclaimers

The vet reviewer date is recorded for each page and displayed in the page metadata. Pages cannot be published with a vetReviewRequired: true flag until the clinical review is complete and signed off.

Automated testing

Every calculator is tested automatically with:

• Known-value tests: At least one primary scenario with all results verified against the published source, plus edge case tests
• Worked example verification: Every worked example input is run through the calculator, and all values are compared programmatically
• Data completeness checks: Every calculator entry must have required fields, source citations, valid date ranges, unique FAQ questions, and minimum link counts
• Schema validation: JSON-LD schema output is verified for correct types, required fields, and valid URLs

Corrections and updates

If you identify an error in any calculator formula, dosage range, toxicity threshold, or educational content, please report it via the feedback form or email hello@crittercalcs.com. Corrections to medical or scientific content are treated as priority issues and reviewed within 48 hours.

All content pages display their last-updated date. We review content regularly against current veterinary guidelines. When veterinary recommendations change, we update the relevant calculators and educational content and note the revision.

Editorial independence

CritterCalcs is independently developed and not sponsored by any pharmaceutical company, pet food brand, or veterinary product manufacturer. Calculator formulas are based solely on published veterinary science, not commercial interests. If advertising is displayed on the site, it does not influence the content, formulas, or recommendations in any calculator.