A single weigh-in tells you almost nothing about a cat. A series of weigh-ins tells you everything: the slow creep upward, the steady loss on a diet, or the sudden drop that needs a vet. This tracker lets you log each weigh-in with a date and a weight, draws the trend as a line chart, and shows the total change and the change per week. Slow changes become visible here long before they become visible on the cat.
Why does the weekly change matter more than the total? Because a loss of 200 grams sounds small, but over four weeks it is 50 grams per week, which is a healthy pace for a 5 kilogram cat. The same 200 grams lost in one week is a warning sign. The tracker divides the total change by the weeks between the first and last entry, so you get a pace, not just a difference. A pace of around 1 percent of body weight per month is sensible for weight loss. Faster needs a vet conversation.
How to weigh a cat accurately at home is worth getting right. The simplest method is to stand on a bathroom scale holding the cat, then subtract your own weight. It works, but bathroom scales round to 100 grams and your own weight shifts during the day. A baby scale is better: put the cat in a basket on the scale, subtract the basket, and you get accuracy to 10 grams. Weigh at the same time of day, ideally before breakfast, and on the same scale every time.
How often should you weigh? Weekly is right when you are changing the diet or when the cat is losing or gaining. Monthly is enough for a stable healthy adult. Daily weighing creates noise: food, water, and litter tray visits move the number by 50 to 100 grams, and chasing daily noise leads to constant portion changes that help nobody. Pick one day a week, write it down, and look at the four-week trend, not the single reading.
Here is a worked example. Weigh-ins on 1 September at 5.0 kilograms and 29 September at 4.5 kilograms give a total change of minus 0.5 kilograms over 4 weeks, which is minus 0.125 kilograms per week, shown rounded as minus 0.1. For a 5 kilogram cat, that is about 2 percent per month, which is at the fast end of the safe range and worth slowing slightly. The chart for those two points is a straight downward line. With six or eight points, the chart shows plateaus, wobbles, and the real direction.
What patterns should worry you? A steady climb of 100 grams a month, month after month, is the classic indoor creep, and it is easy to fix early with a 5 to 10 percent portion cut. A sudden drop of more than 5 percent in a month, or any drop combined with less appetite, more thirst, vomiting, or lethargy, needs a vet promptly. A flat line during a diet, for three weeks or more, usually means treats, measuring, or a neighbour feeder, not a broken metabolism. Check those before cutting further.
The chart is the most honest part of the tool. Numbers in a list blur together, but a line going up or down is obvious at a glance. Show the chart at the vet visit: a vet can read a six-month trend in seconds and separate a diet problem from a medical problem. Take a screenshot or print the page before the visit, since the entries in this tool stay in the page session and are not saved to an account. For a permanent record, copy the table into a notebook or a spreadsheet each month.
Children and other family members can help with weighing, and it is a good routine to share. One person should own the record, though, so entries are not duplicated or missed. Keep the scale in the same place, keep the routine on the same day, and keep the cat calm: a treat after weighing, taken from the daily ration, makes the next weigh-in easier. A cat that fears the scale will struggle, and a struggling cat gives a false reading.
Senior cats deserve closer tracking. Muscle loss in older cats can hide behind a steady scale weight, because fat replaces muscle gram for gram. Feel the spine, hips, and shoulders each month alongside the weigh-in, and note mobility: jumping less, hesitating at stairs, or sleeping much more. A senior that holds weight but loses muscle still needs a vet conversation about protein, joints, and kidney health. The tracker catches the weight part. Your hands catch the rest.
To sum up, tracking turns guessing into knowing. Log each weigh-in, watch the chart, read the weekly pace, and act on the trend rather than one number. A few minutes a month of weighing gives you the earliest warning of weight problems, and the clearest record for your vet. Start today, add the next weigh-in next week, and let the line tell the story.