About dogcalcs

dogcalcs is a collection of 39 free, browser-based calculators for dog owners.

The idea

Dog owners search for very specific numbers: how much to feed, whether what the dog just ate is dangerous, how old the dog really is, what size crate to buy. The existing answers are usually a calculator that shows a number with no explanation, wrapped in a thousand words written for a search engine rather than a person.

This site does the opposite. The calculator sits at the top of the page, the formula and its source sit underneath it, and there is no padding in between.

Principles

  • Show the working. Every tool prints the formula it used and where the numbers came from.
  • Test the math. Calculation code is separate from interface code and covered by unit tests. See the methodology.
  • Refuse to guess. Invalid input produces an error, never a plausible-looking wrong answer.
  • Stay fast. Pages are static HTML. Only the calculator itself loads any JavaScript, and it loads after the page is readable.
  • Keep your data. Calculations run in your browser. Nothing you enter into a calculator is sent anywhere, and the only data the site collects at all is aggregate, cookieless page-view counts. See the privacy page.

Who writes this

dogcalcs is written and built by Ashar Islam, founder and developer, dogcalcs. It is an independent site, not a veterinary practice.

I am a software developer, not a veterinarian. That is the most important thing to know about this site, so it is on the page rather than buried in a disclaimer. I built dogcalcs after searching for how much to feed my own dog and finding page after page that gave a number with no formula, no source and no way to tell whether it had come from a veterinary reference or from nowhere at all.

Here is how I try to compensate for not being a vet:

  • I do not invent numbers. Every constant on this site is taken from a named veterinary guideline, textbook or peer-reviewed paper, and the reference is printed on the page that uses it. If I cannot find a source for something, the page says it is convention rather than dressing it up as science.
  • I show the arithmetic. The formula is written out on every tool page, so you or your vet can check the result rather than trusting it.
  • I test the code. Calculation logic is separated from the interface and covered by unit tests, so a typo in a constant fails a test instead of reaching your dog.
  • I send you to a vet where it matters. The toxicity tools give a poison control number before they give you a number, because in those cases a phone call beats a calculator.
  • Reviewer fields are already in place. Every tool page can carry a “Medically reviewed by” line the moment a veterinarian reviews it. None of them claim that today, because none of them have been.

The full reference list is on the sources page. All 39 tools were last read end to end for accuracy on September 8, 2026. Nothing here is a substitute for professional advice; please read the medical disclaimer.

If you are a veterinarian willing to review a page, or you have spotted something wrong, I would genuinely like to hear from you. Get in touch.

Corrections

If a formula or a constant is wrong, we want to know. Get in touch and include the source you think we should be using.