About this site
Hi, I’m Josh. I run this site. Every formula and every page on it is checked through our published review method. It exists because the feeding information most owners rely on — the chart printed on the back of the bag — is a population average, not a plan for any individual animal.
Who writes this
I started petportioncalc.com for a simple reason: pets deserve better than a guess. The small team behind the calculators shares that bias — we would rather show you the math, with every number you can re-check, than ask you to take our word for it.
My name is Josh. I founded and run petportioncalc.com. The calculators and charts are built by a small team and verified through our published review method. That is the whole of my claim — I am not a veterinarian, I do not have a veterinary qualification, and I am not going to imply otherwise by borrowing a title.
What I can tell you is what I actually do here. Every number published on this site comes out of one calculation engine, so the chart, the calculator and the reference dataset cannot disagree with each other without someone noticing. Every source cited is one we checked against the specific claim it supports, and where we could not reach a document, the page says so rather than pretending otherwise. When a figure is an assumption — kibble density, for instance — the page says so instead of presenting it as a measurement.
Where I am not qualified to answer, the page says that too. Any question about your individual animal's health belongs with your vet, and the pages here are written to hand you back to them at the right moment rather than to keep you on the site.
What is on the site, in numbers
As of October 2026: 81 pages across dog and cat feeding, of which 62 are full guide pages and the rest are calculators, reference pages and legal pages. Eight CC BY 4.0 illustrations, free to reuse with a credit line. An open reference dataset published as JSON and CSV, so the numbers can be re-computed rather than taken on trust. One payment route (affiliate links, disclosed on the pages that carry them) and no other monetisation.
If you find an error, the correction matters more to me than the page looking right. Write to me with the page and the figure, and I will either fix it or tell you why I think the figure stands.
How this site makes decisions
Four rules that apply to every page, and that you can check against the pages themselves:
- Calories per kilogram, not percentages. A guaranteed analysis tells you protein and fat percentages; it does not tell you energy. Percentages cannot be compared across foods without the moisture content, so this site works from kcal/kg and kcal per cup.
- A range, not a false single answer. Where published sources genuinely disagree, the page shows the range and says which figure it applies, rather than averaging them into a number nobody published.
- Cite what can be opened. National Research Council, WSAVA, AAHA and the MSD Veterinary Manual — documents a reader can go and read. Not summaries of summaries.
- Never invent an expert. No page here carries a reviewer's name or a "medically reviewed" badge, because there is no veterinarian signing them. The review note on each page describes a process, not a person.
Why this calculator exists
Feeding charts are built from the same energy equations used on this site, but they are written for a broad population and rounded upward. A chart cannot know that your dog is neutered, eight years old, and walks twice a day. The calorie figure printed on the packet is the number that lets you work out an amount for your own animal — so this site shows its working instead of just handing you a number.
How the numbers are produced
Every calculation runs the same two-stage method used in veterinary nutrition:
- Resting Energy Requirement:
RER = 70 × (body weight in kg)0.75 - Maintenance Energy Requirement:
MER = RER × life-stage factor
The life-stage and activity factors follow the National Research Council’s Nutrient Requirements of Dogs and Cats (2006) and the WSAVA Global Nutrition Committee guidelines. The full factor tables are published on the calculator page, so you can check any result by hand.
How the content is checked
Formula values are checked against the published NRC and WSAVA references and cross-checked against several independent veterinary sources. Every calculation path is covered by an automated test suite that must pass before a new version goes live. Pages are reviewed and updated periodically. How we check every number →
What this site is not
It is also not a diagnostic tool and not a substitute for a veterinary examination. A calorie figure cannot detect an illness, and a feeding amount cannot tell you whether your animal is well. Those are different jobs, done by different people.
This is an estimation tool, not veterinary advice. It does not diagnose or treat any condition. For anything specific to your pet — especially puppies, pregnant or nursing animals, and pets with a medical condition — please consult your veterinarian.
How this page was checked: Numbers traced to NRC (2006), WSAVA and AAHA guidance; units re-derived independently; safety statements limited to the species they were established for. Our review method
Site updates
- September 30, 2026 — Launched with the dog and cat calorie calculators and portion tools.
- October 2026 — Built out the full content library: feeding guides, portion references, and body-condition resources. Every page is checked through our published review method.
- October 2026 — Added the feeding log (v1: save feeding records; v2: photo attachment and one-tap summary export; v2.1: fully inline forms, no browser dialogs).
- October 2026 — Reorganized site navigation with a complete tools index; reviewed and updated the privacy and cookie policies.
Contact
Email: contact@petportioncalc.com
Reviewed and updated: 2026-10-20
The illustrations used across this site (body condition, feeding charts) are free for other pet blogs to use under CC BY 4.0 — just credit us.