Daily calories and grams for a 18 lb (8.2 kg) cat
Resting energy for 8.2 kg is 338 kcal (70 × 8.20.75). 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 3,800 kcal/kg | g at 4,200 kcal/kg |
|---|---|---|---|---|
| Neutered adult | 406 | 119 | 107 | 97 |
| Intact adult | 473 | 139 | 125 | 113 |
| Inactive or prone to weight gain | 338 | 99 | 89 | 81 |
| Kitten | 845 | 249 | 222 | 201 |
These are averages from the Merck/WSAVA energy factors. Your cat may need 10 to 20% more or less. Check the energy on your own food's label and use the calculator below.
Meals, treats and cost
| Two meals a day (neutered adult) | 53 g each |
|---|---|
| Three meals a day | 36 g each |
| Treat allowance (10% of calories) | 41 kcal: 20 pieces of 2 kcal, or 5.1 of 8 kcal |
| Dry food as a share of body weight | 1.3% a day |
| Calories per kilogram of body weight | 49.7 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 | 4.00 | 6.00 | 8.00 |
|---|---|---|---|
| Dry food, 3,800 kcal/kg | 12.81 | 19.22 | 25.62 |
| Wet food at 1,000 kcal/kg (price per kg: 3.00, 5.00, 7.00) | 36.52 / 60.86 / 85.20 | ||
How long a bag lasts
| Bag size | 2 kg | 4 kg | 8 kg |
|---|---|---|---|
| Days at 107 g a day | 19 | 37 | 75 |
On wet food only, a 18 lb (8.2 kg) cat needs about 4.8 cans of 85 kcal a day.
A sample day for a 18 lb (8.2 kg) cat
One way to lay out a neutered adult's day on a 3,800 kcal/kg dry food, with treats counted inside the total.
| Time | What | Amount |
|---|---|---|
| Morning | Meal | 48 g |
| During the day | Treats and training rewards (counted) | 41 kcal |
| Evening | Meal | 48 g |
| All day | Fresh water | Always available |
Meals are smaller than the table above because the treat allowance of 41 kcal is taken out of the day's 406 kcal: 365 kcal of meals is 96 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 3,800 kcal/kg for a neutered adult needing 406 kcal.
| Share of calories from wet food | Wet food | Dry food |
|---|---|---|
| 25% | 101 g | 80 g |
| 50% | 203 g | 53 g |
| 75% | 304 g | 27 g |
Do not add wet food on top of the full dry amount: that doubles the calories it replaces.
How 18 lb compares with nearby weights
| Weight | kcal a day (neutered adult) | g of 3,800 kcal/kg food | kcal per kg of body weight |
|---|---|---|---|
| 14 lb (6.4 kg) | 336 | 88 | 52.9 |
| 15 lb (6.8 kg) | 354 | 93 | 52.0 |
| 16 lb (7.3 kg) | 371 | 98 | 51.2 |
| 18 lb (8.2 kg) | 406 | 107 | 49.7 |
Why a cat 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 cats on this page already show the effect: calories per kilogram fall as weight rises, from the smallest to the largest cat. At 18 lb (8.2 kg), the neutered figure is 49.7 kcal per kg of body weight.
What changes your cat'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 18 lb (8.2 kg) cat eat a day?
A neutered adult of 18 lb (8.2 kg) needs about 406 kcal a day. On a 3,800 kcal/kg dry food that is about 107 g. Intact and inactive cats need 473 and 338 kcal.
How many meals a day for a 18 lb cat?
Two meals of about 53 g, or three of about 36 g, using the same 3,800 kcal/kg food. Your vet may suggest a different pattern.
How many treats can a 18 lb cat have?
Treats should stay within about 10% of daily calories, which is 41 kcal: 20 pieces of 2 kcal or 5.1 pieces of 8 kcal. Subtract them from the meals.
Other weights
Related guides
- How many calories does a cat need?
- How many grams of dry food does a cat need?
- Cat feeding chart by weight
- How much wet food should a cat eat?
How we calculate: RER = 70 × kg0.75, times the life-stage factor, as set out on Formulas & sources. This page is general information, not veterinary advice; ask your vet about your cat.