Dog weight loss calculator

Enter your dog's weight and its body condition score or a target weight. You get daily calories, how many weeks the loss will take at a safe pace, and a weigh-in plan.

Tim de JongUpdated October 2, 20266 min read

Your dog

Current weight

Set the target by

Body condition score

1 to 9, ideal is 4 or 5. Not sure? Use the body condition checker.

Heavy: Ribs hard to feel under heavy fat. Fat pads over the lower back and base of the tail. Waist barely visible or gone.

Pace

Cornell's vets: 1 to 2% of body weight a week is safe

Food calories

Optional, kcal per cup on the bag

kcal

Calories per day

860kcal

To go from 75 to 63 lb in about 19 weeks at 1% a week. Treats come out of this total.

To lose: 12.5 lb (20% over)
Weeks at 2% / 1%: 10–19
First week: −0.8 lb
Treat budget (10%): 86 kcal
Cups per day: add kcal/cup
After the goal: ~1,200 kcal

Weigh-in plan (every 2 weeks)

Expected weight every two weeks
Week	Expected weight
Start	75.0 lb
Week 2	73.5 lb
Week 4	72.0 lb
Week 6	70.6 lb
Week 8	69.2 lb
Week 10	67.8 lb
Week 12	66.5 lb
Week 14	65.2 lb
Week 16	63.9 lb
Week 18	62.6 lb
Week 20	62.5 lb

Agree the plan with your vet. Feeding at or below resting needs is where AAHA recommends a therapeutic weight-loss diet, so your dog still gets all its nutrients.

RER at the target = 70 × 28.3 kg^0.75 = 860 kcal. Weight loss = 1.0 × RER (AAHA) = 860 kcal a day. Weeks = ln(target ÷ current) ÷ ln(1 − 0.01) = 18.1.

A starting point based on AAHA guidelines, not a prescription. Every dog responds differently: agree the plan with your vet, especially for very overweight dogs or dogs with health problems, and adjust it at each weigh-in.

How the dog weight loss calculator works

The plan has three numbers: a target weight, a daily calorie allowance and a pace. The target comes from your dog's body condition score. AAHA's guidelines treat each point above the ideal score of 5 as about 10% extra weight, so a dog scoring 7 is about 20% over (our ideal weight calculator shows the alternative methods).

Calories follow AAHA's energy table for weight loss: 1.0 times the resting energy requirement (RER), worked out for the target weight, not today's.

Daily calories = 70 × (target weight in kg)^0.75 × 1.0

Worked example: a 75 lb (34 kg) dog scoring 7 has a target of about 62.5 lb (28.3 kg). Its RER at that weight is about 860 kcal, so it eats about 860 kcal a day, treats included. At 1% a week it reaches the target in about 19 weeks; at 2% a week, about 10.

How fast should a dog lose weight?

Cornell's Riney Canine Health Center says dogs can safely lose 1 to 2% of their body weight a week: half a pound to a pound a week for a 50 lb dog. Losing faster suggests calories are cut too hard or that something else is wrong. Because each week's loss is a percentage of a shrinking weight, the pounds come off a little more slowly towards the end.

Weeks to reach the target, by how far over it the dog starts. Rounded up.
Starting weight vs target	At 1% a week	At 1.5% a week	At 2% a week
10% over (score 6)	10 weeks	7 weeks	5 weeks
20% over (score 7)	19 weeks	13 weeks	10 weeks
30% over (score 8)	27 weeks	18 weeks	13 weeks
40% over (score 9)	34 weeks	23 weeks	17 weeks

Dog weight loss calories chart

Daily calories for weight loss by target weight, and a rough starting point once the target is reached. Dogs that have been overweight count as obesity-prone, which the Merck Veterinary Manual puts at 1.4 × RER for maintenance.

kcal per day, rounded to the nearest 10. Treats included.
Target weight	During weight loss (1.0 × RER)	After, to maintain (1.4 × RER)
10 lb (5 kg)	220	300
15 lb (7 kg)	290	410
20 lb (9 kg)	370	510
30 lb (14 kg)	500	690
40 lb (18 kg)	620	860
50 lb (23 kg)	730	1,020
60 lb (27 kg)	830	1,170
70 lb (32 kg)	940	1,310
80 lb (36 kg)	1,030	1,450
100 lb (45 kg)	1,220	1,710

Food, treats and exercise

Measure food by weight on a kitchen scale if you can, because scoops vary. Keep treats, chews and scraps under 10% of the daily calories (the calculator shows that budget) and switch to low-calorie treats or pieces of the day's kibble. When the plan cuts calories to resting needs or below, AAHA recommends a therapeutic weight-loss food: these are fortified so your dog still gets enough protein and micronutrients, and added fiber and protein help it feel full.

For activity, Cornell suggests low-impact exercise such as walking or swimming, increased gradually so an unfit dog doesn't get hurt. AAHA also suggests puzzle toys and automatic feeders, and replacing some food-based attention with walks, play or grooming.

Weigh-ins, plateaus and keeping it off

Weigh your dog at least every two weeks, on the same scale and at the same time of day. If it is losing faster than 2% a week, feed a little more; if it has not lost anything over two or three weigh-ins, recheck every source of food before cutting further, then ask your vet. AAHA's guidelines say calorie intake should be adjusted by tracking weight and body condition, and that failing to reach or keep the target is common, with owners not sticking to the plan a major reason.

It is worth the effort. In a study of 50,787 neutered pet dogs across 12 breeds, dogs that were overweight in middle age died younger in every breed. Once your dog reaches its target, move to maintenance calories, keep weighing regularly, and check its body condition rather than relying on the scale alone.

Frequently asked questions

Why are the calories based on the target weight, not the current weight?

AAHA's guidelines base weight-loss calculations on ideal weight because energy needs follow the dog's lean body mass, and an overweight dog's extra weight is mostly fat. Feeding for the target weight creates a steady deficit without having to guess how much to cut.

My dog isn't losing weight. What should I do?

First check every source of food: treats, chews, table scraps, food used for pills and another pet's bowl all count. Weigh the food rather than scooping it. If the weight still hasn't moved after a few weigh-ins, ask your vet; some dogs need a lower calorie level under supervision, and a medical check rules out other causes.

Is it safe for a dog to lose weight quickly?

No. Cornell's Riney Canine Health Center puts a safe pace at 1 to 2% of body weight a week. Faster loss can mean calories have been cut too far, or it can be a sign of illness, so mention any sudden weight loss to your vet.

How much exercise helps a dog lose weight?

Diet does most of the work, but activity helps keep muscle while fat comes off. Cornell recommends low-impact exercise such as walking or swimming, built up slowly so an unfit dog doesn't get injured. Swapping some food rewards for play or a walk also helps.

Can I just feed less of my dog's normal food?

For a small cut, often yes. For bigger cuts, at or below resting energy needs, AAHA recommends a therapeutic weight-loss diet, because those foods are fortified so the dog still gets enough protein, vitamins and minerals from fewer calories.

Sources

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