How Much to Feed a 40 lb Dog (18.1 kg)

Quick answer A neutered adult dog of 40 lb (18.1 kg) needs about 985 kcal a day, which is about 274 g of a 3,600 kcal/kg dry food. Weigh your dog monthly and adjust by about 10% if the trend is wrong.

Daily calories and grams for a 40 lb (18.1 kg) dog

Resting energy for 18.1 kg is 615 kcal (70 × 18.1^0.75). Multiply by the factor for the life stage to get the day's energy, then divide by the food's kcal per gram.

Life stage	kcal a day	g at 3,400 kcal/kg	g at 3,600 kcal/kg	g at 3,800 kcal/kg
Neutered adult	985	290	274	259
Intact adult	1,108	326	308	291
Inactive or prone to weight gain	862	253	239	227
Puppy under 4 months	1,846	543	513	486
Puppy 4 months to adult	1,231	362	342	324

These are averages from the Merck/WSAVA energy factors. Your dog may need 10 to 20% more or less. Check the energy on your own food's label and use the calculator below.

Meals, treats, water and cost

Two meals a day (neutered adult)	137 g each
Three meals a day	91 g each
Treat allowance (10% of calories)	98 kcal: 33 pieces of 3 kcal, or 2.6 of 38 kcal
Water (about 50 mL per kg)	907 mL (range 726 to 1,089); call the vet above 1,814 mL
Dry food as a share of body weight	1.5% a day
Calories per kilogram of body weight	54.3 kcal per kg

Monthly food cost at example prices

Cost = grams a day × 30 ÷ 1,000 × price per kg. The prices are examples; use your own.

Price per kg	3.00	4.00	5.00	6.00
Dry food, 3,600 kcal/kg	24.62	32.82	41.03	49.23

How long a bag lasts

Bag size	2 kg	5 kg	10 kg	15 kg
Days at 274 g a day	7	18	37	55

A sample day for a 40 lb (18.1 kg) dog

One way to lay out a neutered adult's day on a 3,600 kcal/kg dry food, with treats counted inside the total.

Time	What	Amount
Morning	Meal	123 g
During the day	Treats and training rewards (counted)	98 kcal
Evening	Meal	123 g
All day	Fresh water (about 907 mL)	Always available

Meals are smaller than the table above because the treat allowance of 98 kcal is taken out of the day's 985 kcal: 886 kcal of meals is 246 g.

If you feed wet and dry together

Split the calories, not the grams. This uses a wet food of 1,000 kcal/kg and a dry food of 3,600 kcal/kg for a neutered adult needing 985 kcal.

Share of calories from wet food	Wet food	Dry food
25%	246 g	205 g
50%	492 g	137 g
75%	738 g	68 g

Do not add wet food on top of the full dry amount: that doubles the calories it replaces.

How 40 lb compares with nearby weights

Weight	kcal a day (neutered adult)	g of 3,600 kcal/kg food	kcal per kg of body weight
25 lb (11.3 kg)	692	192	61.0
30 lb (13.6 kg)	794	220	58.3
35 lb (15.9 kg)	891	247	56.1
40 lb (18.1 kg)	985	274	54.3
45 lb (20.4 kg)	1,076	299	52.7
50 lb (22.7 kg)	1,164	323	51.3
55 lb (24.9 kg)	1,250	347	50.1

If your 40 lb dog is overweight

Using the rule that each body-condition point above 5 (of 9) is about 10% over ideal weight, here is what a weight-loss plan could look like. The calorie target is 1.0 times resting energy at the goal weight, and the pace is 1 to 2% of body weight a week (AAHA 2014). Your vet should confirm the goal and the plan.

Body condition	Goal weight	kcal a day	g of 3,600 kcal/kg food	Weeks at 2% to 1% a week
6 of 9	16.5 kg (36.4 lb)	573	159	5 to 10
7 of 9	15.1 kg (33.3 lb)	537	149	10 to 19
8 of 9	14.0 kg (30.8 lb)	505	140	13 to 27

Not sure of your dog's score? The Dog Body Condition Score tool shows how to check, and the Dog Weight Loss Calculator works from your own goal weight.

Age and life stage if 40 lb (18.1 kg) is your dog's adult weight

Age charts group dogs by adult size. At 40 lb (18.1 kg) the size group is medium, which adds 5 human years for each dog year after the second.

Dog's age	Human years (size chart)	Human years (epigenetic formula)
1 year	15.0	31.0
3 years	29.0	48.6
5 years	39.0	56.8
8 years	54.0	64.3
10 years	64.0	67.8
12 years	74.0	70.8

Why a dog twice as heavy does not eat twice as much

Energy needs rise with body weight to the power 0.75, not in a straight line. Moving from 40 lb to 45 lb is a 13% weight increase but only about 9% more calories. At 40 lb (18.1 kg), the neutered figure is 54.3 kcal per kg of body weight.

What changes your dog's number

Neutering and activity. The table shows a 10 to 30% spread between stages.
The food. A richer food means fewer grams for the same calories.
Treats. They count within the daily total.
Weight trend. Weigh monthly, score body condition and adjust by about 10%.
Health. A pet on a veterinary diet or with a health condition should follow the vet's plan.

Frequently asked questions

How much should a 40 lb (18.1 kg) dog eat a day?

A neutered adult of 40 lb (18.1 kg) needs about 985 kcal a day. On a 3,600 kcal/kg dry food that is about 274 g. Intact and inactive dogs need 1,108 and 862 kcal.

How many meals a day for a 40 lb dog?

Two meals of about 137 g, or three of about 91 g, using the same 3,600 kcal/kg food. Your vet may suggest a different pattern.

How many treats can a 40 lb dog have?

Treats should stay within about 10% of daily calories, which is 98 kcal: 33 pieces of 3 kcal or 2.6 pieces of 38 kcal. Subtract them from the meals.

My 40 lb dog is overweight. How many calories should it eat to lose weight?

If your dog is at body condition 7 of 9 (about 20% over ideal), a goal weight is about 15.1 kg (33.3 lb). A common weight-loss target is 1.0 times resting energy at the goal weight: about 537 kcal a day, or 149 g of a 3,600 kcal/kg food. At 1 to 2% of body weight a week that takes about 10 to 19 weeks. Your vet should confirm the goal and the plan.

How much water should a 40 lb dog drink?

About 907 mL a day (range 726 to 1,089 mL). Drinking more than about 1,814 mL a day is a reason to call your vet.

Other weights

Related guides

How we calculate: RER = 70 × kg^0.75, times the life-stage factor, as set out on Formulas & sources. This page is general information, not veterinary advice; ask your vet about your dog.