Rabbits are hay eaters first and everything else second. Their teeth never stop growing, and their gut is built to keep moving all day on fibre. So when owners ask "how much should I feed my rabbit?", the real answer starts with hay, not the pellet bag.
Welfare groups such as the RSPCA and the Rabbit Welfare Association describe the same shape: roughly 85% hay or grass, about 10% fresh leafy greens, and only about 5% pellets. Treats are tiny extras. Hay should never run out, so the amount that matters is "always some left".
The RSPCA suggests 25 g (about one egg cup) of pellets per kg of body weight. The Rabbit Welfare Association says 15 g per kg and describes pellets as just 5% of the diet. The calculator above shows both ends. Both are small amounts, so ask your vet which suits your rabbit's size and body condition. Whichever you choose, pick plain pellets rather than muesli-style mixes, where rabbits pick out the tasty bits and leave the fibre.
Chewing hay grinds the teeth down as they grow, and the fibre keeps food moving through the gut. A rabbit that fills up on pellets or sugary treats eats less hay, and that is how dental and tummy problems start. If your rabbit leaves hay and goes straight for the pellet bowl, cut the pellets back a little (within the range above) so hay becomes the main meal. Fresh water should always be available too.
A rabbit that stops eating or pooing for even a few hours needs a vet quickly, as rabbit digestion can slow dangerously. Soft or tiny droppings, drooling, or dropping food from the mouth are also reasons to book a check. Do not change the diet of an ill rabbit on your own.
Hay all day, a handful of greens, a measured spoon of plain pellets. The vet decides anything beyond that.
This guide is general care advice, not veterinary advice.