How much hamsters eat depends on their size, but roughly, hamsters will eat one or two teaspoons of their dry food mix a day. If you notice that your hamster is storing huge amounts of its dry food in its bedding, then you might be feeding it too much. If all the food disappears very quickly, then you might want to increase the amount.
Hamsters are only little, so they only need small amounts of food
If your hamsters are very small, like Roborovskis, then they may need less than one teaspoon. If you own a larger hamster like a Syrian, then it may need a little more. Pregnant or recovering hamsters may also need more food than usual. It’s likely that you will have to use your judgement to adjust how much you feed your hamster on a pet-by-pet basis.