Pet Weight Loss Target & Timeline Calculator
Estimate a safe weekly weight loss rate and timeline to target weight for dogs and cats, plus a starting daily calorie estimate based on target/ideal weight.
Species
Current weight (kg)
Target / ideal weight (kg)
Not sure of the target? Sanity-check it against this site's Adult Breed Weight Reference Chart.
How to use this tool
Safe weekly rate
Dogs: 1-2% of body weight per week. Cats: a more conservative 0.5-1% per week, given the risk of hepatic lipidosis if a cat becomes anorexic during a rapid weight loss plan.
Timeline
Total weight to lose (kg) = current weight − target weight. Using the low end of the species' safe weekly rate gives a slower, more conservative timeline estimate; using the high end gives a faster but still safe upper-bound estimate.
Starting calories
A common starting point is calculating RER (70 × target weight0.75) on the target/ideal weight rather than current weight, then adjusting based on actual progress from weigh-ins every 2-4 weeks.
Frequently asked questions
What is a safe rate of weight loss for a dog or cat?
1-2% of body weight per week for dogs; a more conservative 0.5-1% per week for cats, given the risk of hepatic lipidosis if a cat becomes anorexic during weight loss.
Why is the safe weight loss rate more conservative for cats than dogs?
Cats are uniquely susceptible to hepatic lipidosis - a serious, potentially fatal liver condition - if they go through a period of inadequate calorie intake or true anorexia, which is more likely to happen if a weight loss plan is too aggressive or if the cat simply stops eating the prescribed diet.
Why calculate starting calories based on target weight instead of current weight?
A common veterinary nutrition approach is to estimate the RER on the target/ideal weight as a starting point for a weight-loss calorie prescription, since feeding based on current/overweight body weight would not create the calorie deficit needed to drive loss - though this is adjusted from there based on actual progress.
How often should a weight loss plan be reassessed?
Every 2-4 weeks with an actual weigh-in is a common recommendation, since individual metabolic rate varies enough that the initial calorie estimate often needs adjustment up or down to keep loss on the safe, targeted track.