Each complete bento presented on Just Bento has a calorie count. This is derived from the following information:
Keep in mind that all calorie counts are approximate, since portion sizes may vary.
Most of the complete bentos (the numbered ones) are around 500 calories or lower. They can easily be made bigger or smaller just by increasing the volume of each component. (I frequently show larger “Guy” variations.)
The capacity of “1 cup” varies from country to country, in a maddening way. In the U.S. it’s about 240ml (236.588238 ml); in Japan it’s 200ml; in the UK it’s 436ml. I use 240ml (standard U.S. cup measure) as an approximimate middle ground, especially for rice. If you are very concerned about every single calorie, it’s best to invest in a good kitchen scale.