The Bento Box

From Lunch In A Box

In Japan, bento box size is described not by its dimensions (inches or centimeters), but instead by its volume or capacity (in milliliters — ml). Why? Because a rule of thumb in Japan is that when you pack a bento box normally (A: 3 parts grain dishes, 1 part protein dishes, 2 parts vegetable dishes; B: without candy, junk food or fatty food; and C: without empty space), calories correspond directly to capacity. So a 600ml box should hold a 600-calorie meal.

Capacity (容量) is usually written on the bento box package and also often on the bottom of the bento box in raised plastic. If you’re not sure of your box’s capacity, you can measure it yourself by filling the box with water, pouring the water into a liquid measuring cup and checking the milliliters (ml) or ccs there. Most, if not all, Japanese eBay sellers should be able to tell you the size of a box in ml if asked.

Here’s a quick height conversion chart in case you don’t know your height in centimeters.

Age (Women) Avg. height (in cm) Calories per meal (kCal) Bento Box Size (in ml)
3-5 85-110 450 400
6-8 116-128 500-550 500
9-11 134-147 600-650 600
12-14 155 770 700
15-17 157 735 700
18-20’s 158 685 600
30’s 157 670 600
40’s 157 670 600
50’s 152 650 600
60’s 152 650 600
70’s 147 520 500
80’s 147 520 500

* Source:

Age (Men) Avg. height (in cm) Calories per meal (kcal)
Bento Box Size (in ml)
3-5 85-110 450 400
6-8 117-128 500-550 500
9-11 133-145 600-650 600
12-14 160 885 900
15-17 170 920 900
18-20’s 171 885 900
30’s 170 885 900
40’s 170 885 900
50’s 165 800 800
60’s 165 800 800
70’s 160 620 600
80’s 160 620 600

* Source:

The recommendation is also to adjust for your level of physical activity and height. But I just use the recommended box size that corresponds with my kid’s ages because my kids are petite, I need my picky eater to eat more, and they are active anyhow.

This box that I got at Daiso is a 580ml in capacity, which should give the corresponding calories when the food is compacted into it. I use them for my older two girls.


This one is a 480ml one that I use for my youngest. For the older two, this is their snack bento boxes.


I didn’t know the capacity of the Tupperware I use for my husband’s bento at first but found out later it came up to 1 liter. That would technically read Big on the calorie count for his height and age. So I guess I could afford a little loose packing in his box.


My Tupperware measured 600ml. Just right.


So now, and importantly, must work on packing the food right.


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