Feline Grimace Scale Calculator

Score the five facial action units and see whether the cat needs pain relief.

The Feline Grimace Scale (FGS) scores five facial action units in cats: ear position, orbital tightening, muzzle tension, whiskers change and head position, each 0–2, for a total of 0–10. A total of 4 or more (score ratio 0.39 or higher) indicates pain that should be treated with analgesia.

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How to use it

Watch the cat at rest for about 30 seconds without handling it.
Score each action unit 0 (absent), 1 (moderately present) or 2 (markedly present); leave a unit blank if you cannot see it.
Read the total and the ratio; 0.39 or above (4/10 with all five units) means give or adjust analgesia.

What you enter

Scores for ears, orbital tightening, muzzle, whiskers and head position

What you get

Total score out of 10 and ratio
Whether analgesia is recommended

Formula

FGS score = sum of 5 action units (0–2 each), range 0–10. Ratio = total ÷ maximum possible for the units scored. Analgesia threshold: ratio ≥ 0.39.

Using a ratio lets you score a cat when one unit is hidden (for example ears covered by a bandage).

Worked example: a cat 2 hours after spay

Input: Ears 1, orbital tightening 2, muzzle 1, whiskers 1, head 1

Result: Total 6/10, ratio 0.60: above the 0.39 threshold

Give rescue analgesia and rescore about an hour later.

Questions

What score on the Feline Grimace Scale needs pain relief?

A total of 4 out of 10 or more, which is a ratio of 0.39 or higher, is the analgesic threshold. If a unit could not be scored, divide the total by the maximum possible for the units you did score.

Can owners use the Feline Grimace Scale at home?

Yes. Studies found that cat owners and veterinary students score the FGS reliably after short training. Score the cat while it is awake and resting, not while it sleeps, eats or grooms.

Does the Feline Grimace Scale detect chronic pain?

It was validated for acute pain, such as after surgery. Chronic pain from arthritis or dental disease often shows as behavior change instead, so a low score does not rule it out.