How Much to Feed a 100 lb Dog (45.4 kg)

Quick answer A neutered adult dog of 100 lb (45.4 kg) needs about 1,958 kcal a day, which is about 544 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 100 lb (45.4 kg) dog

Resting energy for 45.4 kg is 1,223 kcal (70 × 45.4^0.75). 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	1,958	576	544	515
Intact adult	2,202	648	612	580
Inactive or prone to weight gain	1,713	504	476	451
Puppy under 4 months	3,670	1,080	1,020	966
Puppy 4 months to adult	2,447	720	680	644

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)	272 g each
Three meals a day	181 g each
Treat allowance (10% of calories)	196 kcal: 65 pieces of 3 kcal, or 5.2 of 38 kcal
Water (about 50 mL per kg)	2,268 mL (range 1,814 to 2,722); call the vet above 4,536 mL
Dry food as a share of body weight	1.2% a day
Calories per kilogram of body weight	43.2 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	48.94	65.25	81.57	97.88

How long a bag lasts

Bag size	2 kg	5 kg	10 kg	15 kg
Days at 544 g a day	4	9	18	28

A sample day for a 100 lb (45.4 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	245 g
During the day	Treats and training rewards (counted)	196 kcal
Evening	Meal	245 g
All day	Fresh water (about 2,268 mL)	Always available

Meals are smaller than the table above because the treat allowance of 196 kcal is taken out of the day's 1,958 kcal: 1,762 kcal of meals is 489 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 1,958 kcal.

Share of calories from wet food	Wet food	Dry food
25%	489 g	408 g
50%	979 g	272 g
75%	1,468 g	136 g

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

How 100 lb compares with nearby weights

Weight	kcal a day (neutered adult)	g of 3,600 kcal/kg food	kcal per kg of body weight
75 lb (34.0 kg)	1,578	438	46.4
80 lb (36.3 kg)	1,656	460	45.6
90 lb (40.8 kg)	1,809	502	44.3
100 lb (45.4 kg)	1,958	544	43.2

If your 100 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	41.2 kg (90.9 lb)	1,139	316	5 to 10
7 of 9	37.8 kg (83.3 lb)	1,067	296	10 to 19
8 of 9	34.9 kg (76.9 lb)	1,005	279	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 100 lb (45.4 kg) is your dog's adult weight

Age charts group dogs by adult size. At 100 lb (45.4 kg) the size group is giant, which adds 7 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	31.0	48.6
5 years	45.0	56.8
8 years	66.0	64.3
10 years	80.0	67.8
12 years	94.0	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. The heaviest dogs on this page already show the effect: calories per kilogram fall as weight rises, from the smallest to the largest dog. At 100 lb (45.4 kg), the neutered figure is 43.2 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 100 lb (45.4 kg) dog eat a day?

A neutered adult of 100 lb (45.4 kg) needs about 1,958 kcal a day. On a 3,600 kcal/kg dry food that is about 544 g. Intact and inactive dogs need 2,202 and 1,713 kcal.

How many meals a day for a 100 lb dog?

Two meals of about 272 g, or three of about 181 g, using the same 3,600 kcal/kg food. Your vet may suggest a different pattern.

How many treats can a 100 lb dog have?

Treats should stay within about 10% of daily calories, which is 196 kcal: 65 pieces of 3 kcal or 5.2 pieces of 38 kcal. Subtract them from the meals.

My 100 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 37.8 kg (83.3 lb). A common weight-loss target is 1.0 times resting energy at the goal weight: about 1,067 kcal a day, or 296 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 100 lb dog drink?

About 2,268 mL a day (range 1,814 to 2,722 mL). Drinking more than about 4,536 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.