A Method You Will Actually Repeat
Accuracy matters less than consistency, so pick the method your cat tolerates. The hold-and-subtract method is simplest: step on bathroom scales holding your cat, note the total, step on alone, and subtract. Do it at the same time of day, ideally before a meal, and use the same scales in the same spot. Cats who wriggle or panic when lifted can be weighed in their carrier using a luggage scale hung from the handle, minus the carrier's own weight recorded once and written on the handle.
Kittens and recovering cats may need fortnightly checks, but for a healthy adult, monthly is a rhythm most owners can keep. Put the weigh-in beside something you already do, such as the flea treatment day or the first of the month, so it becomes routine rather than another chore to remember.
What to Write Down Besides the Number
Record the date, the weight, and one short note: eating normally, fussier than usual, new food started, more active since the weather cooled. Those notes turn a column of numbers into a story your vet can interpret. A stable weight with a note about reduced appetite reads differently from the same weight during a house move, and a gain that coincides with a new treat habit has an obvious first explanation to test.
Keep the units consistent and write them every time. Mixing pounds and kilograms across entries is a surprisingly common way to manufacture a fake weight swing that worries everyone until someone spots the switch.
Why the Trend Beats Any Single Reading
Cats are skilled at looking fine. A gradual loss spread over six months can be invisible in daily life because you see the cat every day, yet it stands out immediately on a dated log, and gradual change is exactly the pattern vets want to hear about early. Steady gain tells its own story about portions, treats from multiple family members, or a neutered indoor cat whose activity has dropped. Bring the log to routine appointments even when nothing seems wrong; pattern-spotting is much easier with twelve entries than with a guess about last year.
Contact your vet sooner rather than waiting for the next routine visit if the log shows a clear, unexplained drop over two or three checks, especially alongside drinking more, eating less, or hiding more than usual. You are not diagnosing anything by weighing; you are handing a professional better evidence, earlier.
Weighing Cats Who Refuse Every Method
Some cats defeat both scales and carriers, especially rescues with handling fears. For them, use the vet's scales opportunistically at every visit and ask reception to print the weight history for your log, filling the gaps between visits with your best home estimate clearly marked as an estimate. Even a sparse series of honest professional readings beats an abandoned perfect system. You can also watch body condition with your hands: ribs felt easily under a thin fat layer, a visible waist from above, and a slight upward tuck from the side suggest a healthy shape for most cats, and a change in what your hands find is worth a vet conversation even before the scales confirm it.
Keep the Log With Her Other Records
A weight log kept in a phone note you later delete helps nobody. File it with her vaccination record and chip details so the whole picture travels together to a new vet, a cattery, or an emergency clinic. Storing that dated weight history as part of KinsLe's Pet Passport means the trend your vet needs sits inside the same portable packet as the rest of her records.