Why weight is the cheapest early-warning system
Weight is the rare health signal that is objective, free to measure, and drifts early in dozens of conditions — thyroid disease, kidney disease, diabetes, dental pain, parasites, heart disease. It also drifts invisibly: living with an animal daily is the worst vantage point for noticing gradual change, which is how a cat loses fifteen percent of itself between annual visits without anyone lying. The scale sees what the eye adapts to.
Weighing dogs and cats at home
Small pets (under ~15 kg): the hold-and-subtract method — weigh yourself on a bathroom scale, weigh yourself holding the pet, subtract. Accurate enough for trend-watching, and it costs nothing.
Cats specifically: a baby scale or kitchen-style pet scale reads to 10 grams and is worth owning for cats on weight plans or seniors, where a quarter-kilogram genuinely matters.
Big dogs: the clinic walk-on scale is free at nearly every practice — walking in monthly just to weigh is normal, encouraged, and doubles as pleasant desensitization to the building.
How often is useful
- Healthy adults: monthly — frequent enough to catch drift, rare enough to sustain
- Puppies and kittens: weekly or biweekly during growth phases; the curve itself is the health record
- Seniors: biweekly to monthly — late-life conditions announce themselves here first
- On a diet or gaining plan: weekly, same day and time, so the plan gets a real feedback loop
Reading the trend like a vet would
Single readings are noise: hydration, meals, and scale differences move a reading a few percent by themselves. Trends are the signal. Percentages beat absolute numbers — half a kilogram is a rounding error on a Great Dane and a tenth of a cat. Rules of thumb worth keeping: unplanned change of five percent says pay attention, ten percent says book a visit, and in cats — where weight loss is disproportionately meaningful — treat any confirmed steady decline as vet-conversation material even under those thresholds. Speed matters as much as size: a drop over three weeks is more urgent than the same drop over a year.
Body condition: the other half of the picture
The scale cannot tell muscle from fat or say what this animal's ideal is — body condition scoring fills that gap. The home version: ribs should be feelable under a light layer without pressing, a waist should be visible from above, and a belly tuck from the side. Ribs invisible under fingers means overweight territory; ribs visible from across the room means under. Vets score this 1–9 at visits — ask where your pet lands and what number to aim for, then your scale trend has a target.
A weight log worth keeping
Four fields: date, weight, which scale, and context (post-diet-change, after illness, summer coat). Context is what makes an odd reading interpretable in a year. Keep the log where trends draw themselves — a printable weight log works on the fridge, and Pawmi charts weight entries per pet over time and puts the curve next to health notes, so a drifting line and its possible cause sit in the same view your vet sees.