How to Use the Cat Grimace Scale at Home: A Step-by-Step Guide to Spotting Feline Pain
Cats are experts at hiding pain, which is exactly why the cat grimace scale was created. This validated tool lets you assess a cat’s pain level just by observing five specific facial features — ears, eyes, muzzle, whiskers, and head position. Below, you’ll learn exactly how to score your cat at home, what the numbers mean, and when it’s time to call the vet.
What Is the Feline Grimace Scale?
The Feline Grimace Scale (FGS) is a facial-expression-based pain assessment tool developed and validated through video recordings and case-control comparisons of client-owned and control cats. It was created by researchers at the Université de Montréal and first presented in the United States at the AVMA Convention in 2019.
Unlike general checklists, the FGS focuses purely on facial changes, which makes it fast and practical for pet owners to use at home — especially after surgery, an injury, or when a cat just “seems off.”
Why Cats Hide Pain in the First Place
As natural prey animals, cats instinctively mask discomfort to avoid appearing vulnerable. That evolutionary habit is part of why pain management in cats is frequently overlooked, and cats tend to receive less analgesic treatment than dogs — not because they hurt less, but because their pain is harder to read.
The 5 Action Units: How Scoring Works
Each of the five facial “action units” is scored 0, 1, or 2: 0 means absent, 1 means moderately present or uncertain, and 2 means obviously present. The five units evaluated are ear position, orbital tightening, muzzle tension, whisker position, and head position, for a maximum possible score of 10.
| Action Unit | Pain-Free (0) | Possible Pain (2) |
|---|---|---|
| Ear position | Upright, facing forward | Flattened or rotated outward |
| Orbital tightening | Eyes open, relaxed | Squinted or partially closed |
| Muzzle tension | Round, relaxed | Tense, elliptical shape |
| Whisker change | Loose, curved | Stiff, pointing forward |
| Head position | Above shoulder line | Held at or below shoulder line |
How to Use the Scale at Home, Step by Step
- Choose the right moment. Observe the cat undisturbed for about 30 seconds — avoid scoring while it’s grooming, eating, vocalizing, or asleep.
- Score each of the five action units from 0–2 using the table above.
- Add up the total score out of 10.
- Compare the result to the interpretation guide below.
- Re-check periodically, especially in the first 24–48 hours after surgery or an injury.
When to Call the Vet
A total score of 4 or above suggests that pain management, including analgesics, should be considered — but this is a screening aid, not a diagnosis. The scale is designed for acute pain and is not considered reliable for chronic conditions.
| Score | What It Suggests | What to Do |
|---|---|---|
| 0–3 | Low likelihood of significant pain | Keep monitoring; note any changes |
| 4 or higher | Possible pain requiring attention | Contact your veterinarian promptly |
If your cat is also hiding, refusing food, or straining to use the litter box, don’t wait — these can be signs of an emergency. The ASPCA outlines emergency warning signs worth knowing regardless of what the grimace score shows.
For a deeper look at everyday feline behavior changes, see our guide to recognizing stress in cats, or explore post-surgery cat care tips.
Frequently Asked Questions
Is the Feline Grimace Scale accurate?
Yes — studies found good overall inter-rater reliability and excellent internal consistency, meaning different observers tend to score the same cat consistently.
Can I use the grimace scale instead of a vet visit?
No. The FGS is a helpful screening tool for spotting possible pain, but it doesn’t replace a veterinary exam or diagnosis.
Does the scale work for chronic pain, like arthritis?
The FGS was developed and validated specifically for acute pain assessment and is not considered reliable for chronic conditions. Ask your vet about tools designed for long-term pain instead.
What’s the best time to check my cat’s grimace score?
Observe your cat undisturbed for about 30 seconds when it isn’t sleeping, eating, grooming, or vocalizing for the most reliable read.
My cat scored a 4 or higher — what now?
Contact your veterinarian. A score of 4 or above suggests analgesics should be considered, but only a vet can determine the right treatment.
Are there other signs of pain besides facial expressions?
Yes — reduced appetite, hiding, changes in grooming, and reluctance to jump are also common. Our guide to subtle pain signs in cats covers these in detail.
Want more practical, vet-informed guides for keeping your cat comfortable and healthy?
Explore More Cat Care Guides on The Happy Pet HubWritten by The Happy Pet Hub Team
Our writers research pet health and behavior topics using veterinary and scientific sources to help US pet owners make informed care decisions. This article is for educational purposes and isn’t a substitute for professional veterinary advice.
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