The maths, with your numbers
No guesswork and no brand chart. This is the same calculation a vet does on paper, so you can check it.
A healthy adult Siamese weighs 5–8 lb (VCA Animal Hospitals cat breed page (quick facts, combined adult range)). Below are daily amounts for that range, for a typical dry cat food (398 kcal per cup, the middle of the cat foods in our list). For your own food, use the calculator above: it is already set to a Siamese weight.
| Weight | Lazy indoor | Spayed or neutered | Intact |
|---|---|---|---|
| 5 lb 2.3 kg | ⅜ cup35 g · 129 kcal | ⅜ cup43 g · 155 kcal | ½ cup50 g · 181 kcal |
| 8 lb 3.6 kg | ½ cup50 g · 184 kcal | ½ cup60 g · 221 kcal | ⅝ cup71 g · 258 kcal |
Daily totals with no treats. Worked out from resting energy (70 × kg0.75) and the AAHA 2021 life-stage factors. Weight source note: VCA quick facts.
Good to know
Most cats are spayed or neutered and live indoors, so the middle column is the usual starting point. Many cats eat some wet food too; tick “Mix with a second food” in the calculator to split the day between wet and dry.