Why can a kibble that costs more per kilo cost less per day?

Because cost per day depends on the ration, not on the price per kilo. A pricier but denser kibble is served in a smaller amount, so the bag lasts longer and the daily spend falls. The effect exists only where the density gap exceeds the price gap. In depth ### The mechanism of the reversal The paradox comes from two variables pulling in opposite directions: price per kilo pushes the cost up, density pushes it down by shrinking the ration. When the density gain outweighs the per-kilo premium, the costly food's cost per day drops below that of the cheap food. This result only appears after calculation, on the specific product. An example puts numbers on it. A kibble at 400 kcal per 100 g serves 150 g for 600 kcal, against 200 g for a kibble at 300 kcal per 100 g: the first uses a quarter less material per day. Surprisingly, that density gap of only 100 kcal per 100 g can be enough to reverse the price-per-kilo ranking, which is why an isolated price per kilo misleads (WSAVA, 2021). ### The conditions for the effect The reversal is neither automatic nor general. It requires a markedly higher density, verified rather than calculated, and a moderate price-per-kilo gap. If the costly kibble is no denser, cost per day follows price per kilo and rises (NorthPoint Pets). The only way to know stays comparing the two costs per day, delivery included. Comparison table | Food | Price per kilo | Density (kcal/100 g) | Ration for 600 kcal | |---|---|---|---| | Kibble A (costly) | higher | 400 | 150 g/day | | Kibble B (budget) | lower | 300 | 200 g/day | | Decisive variable | density, not price per kilo | gap to verify | final cost per day |