How Fast Should a Dog Lose Weight?

Quick answer AAHA weight management guidelines describe a safe pace of about 1 to 2% of body weight a week. A 30 kg dog should lose about 0.3 to 0.6 kg a week, so a 5 kg loss takes roughly 10 to 19 weeks. Losing faster than 2% a week is not safer and should be checked by your vet.

Everyone who puts a dog on a diet wants to know how long it will take. Everyone also worries about doing it wrong. The question “how fast should a dog lose weight?” has a clear answer in the veterinary guidelines, and the answer is a percentage, not a number of kilograms. This guide explains the standard pace, turns it into kilograms per week and weeks to goal, and shows how to tell when the pace is too fast, too slow or just right.

The standard: 1 to 2% of body weight a week

AAHA’s weight management guidelines describe a safe rate of loss of about 1 to 2% of body weight per week. The reason it is a percentage is practical: a 5 kg dog losing 0.5 kg a week would be dropping 10%, which is far too fast, while a 40 kg dog losing 0.5 kg a week is losing about 1.25%, which is fine. Using a percentage gives every dog a rate that suits its size.

The aim is to lose fat, not muscle, and a steady pace is better for that. A slower pace is perfectly acceptable, and your vet may choose it for older dogs or dogs with other health problems.

What the percentage means in kilograms per week

Starting weight	1% a week	2% a week	Goal weight (example)	Weeks at 1%	Weeks at 2%
8 kg (17.6 lb)	0.08 kg	0.16 kg	6.5 kg	21	11
12 kg (26.5 lb)	0.12 kg	0.24 kg	10 kg	19	10
20 kg (44 lb)	0.20 kg	0.40 kg	16 kg	23	12
30 kg (66 lb)	0.30 kg	0.60 kg	25 kg	19	10
40 kg (88 lb)	0.40 kg	0.80 kg	32 kg	23	12
50 kg (110 lb)	0.50 kg	1.00 kg	40 kg	23	12

The weeks come from applying the percentage each week to the weight the dog has at that point, so the weekly kilograms shrink a little as the dog gets lighter. The Dog Weight Loss Calculator works out the weeks for any current and goal weight, and the Pet Weight Goal Date Calculator turns them into a target date.

A worked example

A dog weighs 30 kg and the goal is 25 kg.

At 1% a week the first week’s loss is 0.30 kg. The weight after four weeks is about 28.8 kg.
The calculator finds that the goal takes about 19 weeks at 1% and about 10 weeks at 2%.
A reasonable plan is to aim for the middle, around 14 weeks, and to expect to be a week or two either side.
Each fortnight, weigh the dog and compare with the plan.

If at week four the dog weighs 28.8 kg you are on pace for 1%, and if it weighs 29.5 kg you are slower than 1%, which is fine as long as the trend is down and the food is measured.

How to check the real pace

The Pet Weight Change Calculator takes two weights and the number of weeks between them and shows the percentage change in total and per week. For example, a dog that goes from 30 kg to 28.5 kg in three weeks has lost 5%, which is about 1.7% a week, inside the standard range. A dog that falls from 30 kg to 26.5 kg in three weeks has lost about 11.7%, nearly 4% a week, which is too fast and needs a call to the vet.

Too fast: warning signs

Weight loss that is faster than 2% a week is not a bonus. Possible causes include:

The calorie budget is too low for this dog.
The dog was weighed on different scales or in different conditions.
The dog is ill, for example from a digestive or metabolic problem.
The dog is losing muscle as well as fat.

Contact your vet if your dog is losing faster than planned, seems tired or weak, refuses food or has changes in drinking or toileting. Do not cut calories further to “keep going”.

Too slow: what to check

If the scale barely moves for three or four weeks, run through this checklist before changing anything:

Is the food weighed on a scale, not scooped?
Have treats, chews or table scraps crept back in?
Is anyone else feeding the dog?
Has the food changed, so that the same grams carry more calories?
Is the scale accurate and used in the same way?

If everything checks out and the dog is still not losing, ask your vet. Some medical conditions make weight loss harder, and a vet can check and adjust the plan.

Why the last kilograms are slower

Near the end the dog weighs less, so the calorie budget is smaller (it is based on the goal weight and does not change as the dog approaches it) while the dog’s actual needs fall as it gets lighter. The gap between what the dog eats and what it uses closes, so the loss slows. This is normal and a good reason to schedule vet checks towards the end of a plan, when the vet can decide whether to adjust the budget or move to a maintenance amount.

Expecting a plateau

Weight loss is rarely a straight line. Small plateaus of a week or two happen, and weights vary from day to day by water and food in the gut. Look at the trend over four weeks, not the last reading, and do not respond to one flat week by cutting food. Our dog weight loss plan lists the weekly routine in more detail, and the guide to calories for dog weight loss shows how the budget is set.

Does pace depend on the dog?

The percentage is the same for all dogs, but practical details differ:

Small dogs: weekly changes are tiny (80 to 160 g for an 8 kg dog), so use accurate scales and look at two-week changes.
Large dogs: the same percentage is a larger amount; check that the dog is not losing muscle.
Older dogs and dogs with health conditions: your vet may choose a slower pace.
Dogs with joint problems: gentle, regular movement matters; ask your vet what is suitable.

Body condition tells you when to stop

The goal is a body condition of 4 to 5 on the 9-point scale, not a number on the scale alone. Each point above 5 is roughly 10% over ideal weight (Laflamme 1997). Re-score every month. When ribs are easy to feel and the waist and tuck are visible, the plan has done its job and you can move to maintenance. Our body condition score chart guide shows how.

Common mistakes

Aiming for a fixed number of kilograms a week regardless of size.
Cutting calories further when the scale stalls for a week.
Weighing on different scales.
Forgetting that treats are part of the budget.
Stopping at the goal weight without a maintenance plan.
Ignoring signs of illness during a diet.

A worked month: from first weigh-in to week four

Tracking the numbers over a month shows what steady loss looks like. Take a dog that starts at 30 kg with a goal of 25 kg, aiming for about 1% a week.

Week	Target weight at 1% a week	A realistic reading	Comment
0	30.0 kg	30.0 kg	Start
1	29.7 kg	29.8 kg	Small change; normal
2	29.4 kg	29.5 kg	On pace
3	29.1 kg	29.4 kg	Slightly slower; hold steady
4	28.8 kg	28.9 kg	On pace

Individual readings bounce by 100 to 300 g, so nobody would change the plan after week 3. What matters is that the line is going down over several weeks. If the dog were at 29.8 kg at week 4, that would be slower than planned, and the owner would check the basics.

Pace for dogs of different sizes

Starting weight	Loss per week at 1%	Loss per week at 2%	What this feels like on the scale
5 kg	50 g	100 g	Hard to see on a bathroom scale; use a kitchen scale
10 kg	100 g	200 g	Two-week changes are clearer than weekly ones
20 kg	200 g	400 g	Visible every two weeks
40 kg	400 g	800 g	Visible weekly

For small dogs, weigh with a more sensitive scale and look at two-week changes. Otherwise it is easy to believe that nothing is happening.

Why the pace is set in percent: an analogy

A person who loses 1 kg a week is losing a small share of body weight, while a hamster that loses 1 g is losing a large share. Dogs span a wide range of sizes, so a percentage keeps the plan sensible for each. That is why guidance says 1 to 2% and not “half a kilo a week”. If you hear advice that gives a flat number for all dogs, treat it with caution.

Questions your vet may ask

What is the dog’s current weight and when was it last measured?
How much and what does the dog eat, including treats?
What exercise does it do?
Has weight changed suddenly?
Are there any other signs, such as changes in drinking, energy or coat?

Bring your weight log and feeding notes. It saves time and helps the vet decide whether the pace is right.

Quick summary

The standard pace is about 1 to 2% of body weight per week.
A 30 kg dog should lose about 0.3 to 0.6 kg a week; to reach 25 kg takes about 10 to 19 weeks.
Faster is not safer; check with your vet if loss is above 2% a week.
If progress stalls, check measuring, treats and who is feeding before changing the plan.
Judge success by body condition as well as the scale.
Use the Dog Weight Loss Calculator and Pet Weight Change Calculator.

Frequently asked questions

How fast should a dog lose weight?

About 1 to 2% of body weight per week, according to AAHA's weight management guidelines. For a 20 kg dog that is 0.2 to 0.4 kg a week.

How long will it take my dog to reach the goal weight?

It depends on the pace. A 30 kg dog going to 25 kg takes about 19 weeks at 1% a week and about 10 weeks at 2% a week.

Is faster weight loss better?

No. Very fast loss risks losing muscle and makes the diet hard to stick to. A steady pace in the 1 to 2% range is the standard.

What if my dog loses weight faster than 2% a week?

Tell your vet. It may mean the calorie budget is too low, the weighing is inaccurate or something else is going on.

What if my dog is losing less than 1% a week?

Check the basics first: measured portions, treats and family members feeding extras. If the scale is stuck for several weeks, ask your vet to review the plan.

How often should I weigh my dog?

Every one to two weeks on the same scale at the same time of day. Single readings are noisy, so look at the trend.

Does the pace slow near the goal?

Often, yes. The calorie budget is smaller for a lighter dog, and the percentage is applied to a smaller weight, so the last kilograms take longer.

Sources

AAHA (2014) Weight Management Guidelines for Dogs and Cats
WSAVA Global Nutrition Guidelines (incl. 9-point BCS charts)
Laflamme D. (1997) Development and validation of a body condition score system for dogs. Canine Practice

Reviewed by the CalcuPaw Veterinary Review Team

Last reviewed 18 Oct 2026 · Meet the review team · This guide is general information, not veterinary advice.