Ordinary People Can Read a Cat's Face
A validated pain scale reads five things in a cat's face. In a study of 1,262 caregivers across 66 countries, owners scored almost as reliably as vets.
Cats conceal pain. That much is repeated everywhere, and it is true, and it leaves owners with an unhelpful conclusion: that you cannot tell.
You can tell. There is a validated instrument for it, it reads a cat's face rather than its behaviour, and — this is the interesting part — it works in the hands of people with no veterinary training.
The instrument
The Feline Grimace Scale was developed and validated by a team at the Université de Montréal and published in Scientific Reports in 2019. The design was deliberately unglamorous. Thirty-five client-owned cats presenting with naturally occurring acute pain were video-recorded undisturbed in their cages, alongside twenty controls. The painful cats were then given pain relief and recorded again an hour later.
Four observers scored still images on five facial action units, each from 0 to 2:
Ear position — from upright and forward, to flattened and rotated outward
Orbital tightening — how far the eyes are squeezed shut
Muzzle tension — round and relaxed, versus tight and elliptical
Whisker position — from a loose curved fan, to straight and pushed forward
Head position — above the shoulder line, versus level with or below it
The results held up on every measure the authors tested. Painful cats scored higher than controls. Agreement between different observers was good, agreement within the same observer across sessions was excellent, and the scale detected the drop in score after analgesia — which is the test that matters, because it shows the instrument is tracking pain rather than tracking something incidental about ill cats. Correlation with an existing validated pain scale was very strong. The paper set a cut-off: a normalised total above 0.39 out of 1.0 suggests analgesia is warranted.
It has since been cited over two hundred times. As feline welfare research goes, this is about as solid as the ground gets.
The finding that matters for owners is not that a scale exists. It is that the scale does not appear to require a veterinary degree to use.
Can owners actually use it
That question was tested directly. A bilingual survey run through International Cat Care in 2021, published in the Journal of Feline Medicine and Surgery in 2023, put ten images of cats at varying pain levels in front of 1,262 cat caregivers across 66 countries, alongside a group of eight veterinarians.
Caregiver scores were not significantly different from the vets' on four of the five action units. The only divergence was muzzle tension, where owners scored slightly higher. Reliability for the total score came out in the range the authors classify as good. Demographic variables — age, gender, country — did not shift the scores.
The honest caveat is in the detail. Reliability was good for ears and eyes, moderate for muzzle, and only reasonable for whiskers and head position. In other words: the two easiest things to see are also the two most reliable. If you are going to look at one thing, look at the ears and the eyes.
More recent work has gone further and built a scale designed for owners from the outset. A 2025 study in Animals developed an owner-assessed feline acute pain scale and tested it against three veterinary instruments in 130 cats. It correlated strongly with the Glasgow composite scale and discriminated well between cats who did and did not need pain relief.
The direction of travel is consistent. Pain assessment in cats is not the exclusive property of clinicians.
What to do with this
Two practical uses, and one thing this is not for.
Use it after surgery. A cat comes home from a dental or a spay and the question is always whether the pain relief is enough. Look at the face, in the cage or the carrier, while the cat is undisturbed — not while you are handling it, because handling changes the face. Ears back and rotated, eyes squeezed, whiskers straight and forward, head low: that is a cat to phone the clinic about.
Use it as a baseline. Look at your cat's relaxed face now, while nothing is wrong, on an ordinary evening. The scale works on change, and change is invisible if you never saw the starting point.
Do not use it to decide not to go. A low score is not a clean bill of health. The scale was validated on acute pain, not on the slow grinding discomfort of arthritis or dental disease, and it says nothing at all about the many serious feline illnesses that are not painful. A cat can score zero and be in kidney failure.
The papers
Facial expressions of pain in cats: the development and validation of a Feline Grimace Scale — Evangelista et al., Scientific Reports, 2019
Can cat caregivers reliably assess acute pain in cats using the Feline Grimace Scale? A large bilingual global survey — Monteiro et al., Journal of Feline Medicine and Surgery, 2023
Development and Validation of an Owner-Assessed Feline Acute Pain Scale — Rojsiripornchai et al., Animals, 2025
The scale itself is freely available, including as a phone app, from the research group that built it.
This is general information, not a diagnosis.
Every cat is a specific animal with a specific history. Use this to ask your vet better questions — not to replace the examination. Spotted an error? Tell us and we will correct it in public.
