Dog weight loss calculator: a safe timeline from your dog’s body condition

1. Target weight. If your vet gave you one, the planner uses it. If not, it estimates one from the score with AAHA’s rule that each point above 5 is about 10% overweight: today’s weight divided by one plus 10% for each point over 5. (AAHA)
2. Rate. It shows the weeks at 2% and at 1% of today’s weight a week, the range VCA and Tufts give, and for a dog scoring 8 or 9 also at 0.5%, which VCA says may suit very overweight dogs. (VCA, Tufts)
3. Weeks. It divides the share of weight to lose by the weekly rate and rounds up. Working on the starting weight follows VCA’s point that losing 1% a week takes twice as many weeks as 2%. (VCA)
4. Exercise. It adds sourced exercise suggestions, grouped by score. No source scales exercise by body condition score, so the grouping is ours. (VCA, PDSA)

It never shows calories or food amounts. Those come from your vet, based on your dog’s ideal weight and adjusted for the individual. (AAHA, VCA)

The sources agree on a narrow range. Tufts and VCA say 1% to 2% of body weight a week, Merck calls about 1% a week a reasonable goal, and VCA allows closer to 0.5% for very overweight dogs. AAHA’s 2021 guideline gives no weekly figure; it refers readers to its 2014 guideline, which we could not open, so we do not quote it. (Tufts, VCA, Merck, AAHA)

Slower is not failure. The AVMA reminds owners that it often takes longer to lose weight than it took to gain it. (AVMA)

• Muscle loss. VCA warns that rapid weight loss can lead to loss of lean muscle. (VCA)
• Missing nutrients. Simply feeding less of the usual food can leave a dog short of nutrients, which is why vets use diets fortified for calorie restriction. (AVMA, AAHA)
• Hidden illness. The AVMA says rapid weight loss can signal a serious health problem. (AVMA)
• Merck puts it plainly: starvation is never a safe or humane way to cause weight loss. (Merck)

Merck says the most successful programmes combine calorie restriction with exercise, and a study of overweight dogs found that those given a training plan kept their lean mass while dogs on diet alone lost some. (Merck, Vitger et al. 2016)

• Brisk walking: start with 30-minute walks at least five times a week, building the brisk part week by week. (VCA)
• Swimming, if your dog likes water: it is easy on the joints. (PDSA)
• A veterinary rehabilitation practitioner, for a dog that is very overweight or sore. (AAHA, VCA)
• Play, walks and brushing in place of food rewards. (AAHA)

Check with your vet first if your dog has a heart or lung problem: the VCA walking plan is meant for dogs without them. Use the daily exercise calculator for your dog’s usual needs, and on warm days check the walk temperature checker: overweight dogs are more at risk of heatstroke. (VCA)

Every source uses the same line: treats under 10% of daily calories. WSAVA adds that human food and table scraps can be unhealthy or even dangerous for dogs. (WSAVA, Merck, VCA, AVMA)

In practice, count every chew and scrap, take treats out of the day’s food allowance, and swap food rewards for attention, a game or a short walk. A puzzle feeder slows meals down; our enrichment ideas include a few. (AAHA)

Every 2 weeks: Merck and VCA both advise it, and VCA suggests an early check within the first week. Another VCA page suggests monthly weigh-ins, so treat monthly as the minimum. PDSA notes that regular weigh-ins make weight loss more successful. (Merck, VCA, VCA, PDSA)

Use the same scale each time, and track the body condition score too: the goal is a score of 4 or 5, not just a number on the scale. (Merck, AAHA)

Most weight gain comes from eating too much or exercising too little. PDSA says hormone conditions are a much rarer cause, but they are worth ruling out before a diet: (RSPCA, PDSA)

• Hypothyroidism, which can cause weight gain without a bigger appetite. (Merck, VCA)
• Cushing’s disease, with a pot belly, panting and obesity among its signs. (Merck, VCA)
• Medicines such as corticosteroids and phenobarbital. (Merck, PDSA)
• Neutering, which lowers energy needs, and breed: some breeds gain weight easily. (AAHA, Pegram et al. 2021)

See your vet before starting a plan, if your dog scores 8 or 9, has a health condition, or stops losing weight across a few weigh-ins. (VCA, VCA)

• Steady loss within the 1% to 2% a week range, checked every 2 weeks. (VCA, Merck)
• A body condition score moving towards 4 or 5: ribs easy to feel, a waist from above. (WSAVA)
• Easier movement: a loss of as little as 6% to 8% of body weight has been shown to improve lameness. (Tufts)
• Staying there. In one follow-up, 48% of dogs that reached their target regained more than 5% of their weight, so keep the habits that got you there. (German et al. 2012, VCA)

It is worth it. In a lifelong study, Labradors fed 25% less lived longer, and Tufts reports that Labradors 10% to 20% overweight lived a median 1.8 years less than their lean siblings. (Kealy et al. 2002, Tufts)

Every figure and threshold on this page comes from the veterinary sources below, and each one is linked where it is used. Where no source gives a cut-off, we say call your vet rather than invent one.