Indoor cats need 20% fewer calories than outdoor cats. But they beg 40% more. The math does not work unless you know the numbers.
I have this argument with clients monthly. "My cat goes outside for an hour a day, so he is active." No. He sits on the porch and watches birds. That is not activity. That is Netflix for cats.
Real outdoor cats roam. They hunt. They climb fences. They expend energy. An outdoor cat might need 1.6 × RER. An indoor cat needs 1.2 × RER. That is a 33% difference in daily calories.
For a 4kg cat:
- Outdoor active: ~280 kcal/day
- Indoor low activity: ~210 kcal/day
70 kcal difference. That is one-third of a cup of dry food. Or almost a full can of wet food. Over a year, that is 25,550 extra calories. Which translates to roughly 7 pounds of fat.
The begging is the real killer. Indoor cats are bored. Food is entertainment. They beg because they have nothing else to do. Not because they are hungry.
I see this with Luna. She begs at 10 PM every night. Not because she needs food — she had dinner at 7 — but because I am sitting on the couch and she wants attention. If I give her a treat, I reinforce the behavior. If I play with her for five minutes, she forgets about food.
Environmental enrichment matters more than most people think. A cat tree by the window. A puzzle feeder. A cardboard box. These things burn mental calories. They reduce begging. They make your life easier.
The calculator has an "indoor" and "outdoor" option. Use the right one. Do not pretend your porch-sitter is a hunter. The numbers matter.
P.S. — If you have an indoor cat and a small apartment, vertical space is everything. Shelves, cat trees, window perches. I live in a 600sqft place and Luna has four vertical levels. She is basically a mountain cat now.