Read the calories on a pet food label

James Wellbeloved Adult Turkey has 3,560 kcal/kg by zooplus's statement, and Whiskas 1+ Adult Chicken has 3,760 kcal/kg by Pets at Home's, both checked 2 November 2026. Neither store prints the number that way. Both give it per 100 g, under different names.

I read these from store pages and the regulation. I can't vouch for what's printed on any bag in your cupboard, so treat the bag as the final word.

Five steps

1. Look under the analytical constituents. The version of Regulation 767/2009 on legislation.gov.uk requires four of them on a complete cat or dog food: crude protein, crude fibres, crude fat and crude ash. Calories aren't on that list. Annex VII says only "if the energy value and/or protein value are indicated", then sets a rule for how. I read that as calories being optional, so a bag may not show them. Check the store page and the feeding guide too.
2. Learn the aliases. I found four on two store sites. Royal Canin Maxi Adult on zooplus says "metabolisable energy". James Wellbeloved says "food energy". Pedigree says "calories that can be burned". Whiskas on Pets at Home says "calculated calorie content" and adds "ME". The Merck Veterinary Manual defines metabolisable energy as the portion of a diet's total energy retained within the body, and it's the figure you want.
3. Convert to kcal per kilo. Labels written per 100 g need multiplying by 10, so 350 kcal per 100 g is 3,500 kcal/kg. Merck notes that a kilocalorie is also written as a Calorie with a capital C, which you'll meet on US pages. They're the same unit.
4. Check that it's as fed. AAFCO's US rule asks for kilocalories per kilogram "as fed", which means the food as it comes out of the bag. Use that for your sums and compare like with like.
5. Test it against the feeding guide. This catches misprints. Pets at Home's guide for Whiskas gives a 4 kg cat 55 to 65 g a day, which at 3,760 kcal/kg is 207 to 244 kcal. Merck's formula for a neutered 4 kg cat, 70 x kg^0.75 x 1.2, gives 238 kcal. Those agree, and that's reassuring. A figure that lands far outside is a reason to go back and reread.

Why "calculated" is on the label

AAFCO's page for pet food start-ups explains one method: a maker takes average lab results and multiplies them by set values, 3.5 for protein and carbohydrate and 8.5 for fat. So a calorie statement can be a sum. Whiskas's wording says as much. Nothing on the zooplus pages tells me how the other three makers arrived at theirs.

Don't run that sum on the percentages printed on a bag. AAFCO says a calorie statement is worked from averages, where US label guarantees are declared as minimums or maximums, so the inputs differ. Your answer would look exact and might not be. That's why I don't estimate a food's calories from its percentages.

When the figure is missing

It happens. Pets at Home's page for AVA Optimum Health Medium Breed lists protein, fat and fibre, and a feeding guide, with no calorie figure. Ask the maker or the store. If nobody will say, compare that food by its kilo price, £3.47/kg, and accept that the comparison is rough.

The US is stricter here. AAFCO says a calorie statement there must sit under a heading titled "Calorie Content", in kcal per kilogram and per familiar unit such as a can or cup. That rule doesn't bind a UK bag.

What to do with the number

Two uses repay the trouble. Divide a day's calories by it to get grams, which is how working out how much to feed your dog goes. Or divide the kilo price by it to get price per 1,000 kcal: James Wellbeloved comes to £0.98 per 1,000 kcal at the price read on 2 November 2026, and Whiskas to £0.84 per 1,000 kcal at the price read on 2 November 2026.

The pet cost calculator takes it from there.