Pet Weight Recheck Tool
Enter two weigh-ins to estimate your pet's weight change and monthly pace. This tool can help you decide when to recheck the weight or review the trend with your veterinary team.
This tool compares two weigh-ins for an adult dog or cat. It does not diagnose obesity, explain the cause of weight change, prescribe calories, or confirm that weight loss is appropriate or safe.
APOP's general monthly planning ranges: about 3% to 5% for dogs and 2% to 3.5% for cats, often less at the start for cats.
These ranges are intentionally conservative for home monitoring. A veterinary team supervising weight loss sets the feeding target, pace, treat allowance, and recheck schedule for the individual pet. A prescribed plan may use a different pace based on health, current intake, body condition, muscle condition, and progress.
Follow your pet's prescribed plan. Do not reduce food, skip meals, or change the plan based on this result alone. A result within the displayed range is not proof that weight loss is safe.
- Contact the clinic promptly if weight loss is unplanned, appetite drops, or your pet seems unwell, even when the result is within the displayed range.
- A cat eating little or nothing for 24 hours needs veterinary assessment the same day. Call sooner if appetite drops. Do not wait 24 hours if the cat seems ill.
- Seek urgent veterinary care for trouble breathing, collapse, or severe weakness.
How to weigh your dog or cat for a more accurate result
For the most accurate comparison, use the same scale and similar conditions for both weigh-ins.
Home weigh-ins can vary. A different scale, a recent meal, a full bladder, a heavy collar or harness, or weighing at a different time of day can make a small change look larger than it really is.
- Use the same scale whenever possible.
- Weigh at about the same time of day.
- Weigh before a meal when possible.
- Remove heavy collars, harnesses, sweaters, or carriers unless you subtract their weight.
- For cats and small dogs, use a baby scale when available.
- If using a home scale, weigh yourself holding your pet, then subtract your weight.
- If the number seems surprising, weigh again before changing the feeding plan.
Monthly ranges, alert thresholds, and calculation method
Rates below the reference range are not automatically a problem or a reason to reduce food. Small changes, very short intervals, and unusual entries may produce a different message before a range comparison is made.
These are APOP calculator review thresholds. They are not proven limits of safety, a diagnosis, or an instruction to change a veterinary prescription.
Calculation: weight change (%) = (later weight minus earlier weight) ÷ earlier weight × 100. The weekly average multiplies this by 7 ÷ elapsed days. The monthly average multiplies it by 30.44 ÷ elapsed days.
The comparison uses the earlier measured weight as its reference. It is a scaled average between two weigh-ins, not a prediction of future weight loss. It does not duplicate the step planner's compounded monthly projections. Estimates from less than 14 days need particular caution. Alerts use unrounded rates. Displayed numbers are rounded.
Review revision: 9 September 2026. Veterinary approval of these published tool settings is required before release.
Choose your pet and units
Enter the earlier weigh-in
Enter the later weigh-in
Your results