The Definitive Guide To Finding Your Ideal Bento Box

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  • July 15, 2015
The Definitive Guide To Finding Your Ideal Bento Box

Whether it’s for being more heathy or saving money, the number of bento users has been increasing rapidly throughout the world. But because there are so many types of bento boxes on the market, many people are having trouble knowing which is the best bento box for them. It’s important that you use one thats in an appropriate size for your diet, or else you will not be able to gain enough energy from your lunch. There are also other factors such as material and functions that you must consider to pick out your ideal bento box for your lifestyle.


Bento boxes (Japanese ones) are usually sold in variety of sizes with increments of 100ml. The amount a person eats per meal differs greatly depending on their age and daily activity level. There is a way to calculate approximately how large your bento box should be. You can use the table below as a basic reference in choosing the right size bento box for you. If you are taller or shorter than the average for your age, you might want to choose a bento box that is a step above or below the recommended size. If your lifestyle is low activity like sitting most of the time in the office or in school, look at the “sedentary lifestyle” column. If you have a job that requires a lot of exercise, like a construction worker, look at the “very active lifestyle” column.

bento sizes for men
bento box sizes for women


Now that you know how big your bento box should be, next let’s look at the three most popular materials that bento boxes are made of. Each material has its own characteristics and will be a factor that you would want to carefully think about before buying a bento box. For example, if you wanted a bento box that is easy to wash, easy to fit in a business bag, and keeps the food delicious, a slim heat retaining type that is made of plastic or metal might be your best choice.



Plastic (polypropylene to be exact) is the most popular material for modern bento boxes. It is the most heat resistant and acid resistant, and one of its biggest advantages is that its microwavable. Also, there are many plastic bento boxes that has a rubber packing which allow you to pack juicy food with less risk of leaking. However, there is a downside of them being hard to wash off the grease and stains from the food, and also being easier to deteriorate making plastic bento boxes shorter lasting compared to metal materials.


Aluminum and Stainless Steel

If you want to prioritize the easiness to wash, aluminum and stainless steel is the best material for you. You will not be able to microwave these material, but there are some models that allow you put to it to direct heat to cook the food inside. Stainless steel especially is good at not having smell stick to the bento box. They are also hard to rust, easy to wash off the greasiness, and very light in weight which makes them a great material in its usefulness.



Wooden bento boxes have been used in Japan since a long long time ago. Japanese cedar and cypress made bento boxes have started to get very popular recently for its fashionable look. Its attractiveness not only reside in its appearance but also in its ability to keep the food cool and moist. Some even have a sterilization effect, and is valued as an excellent material to keep the food delicious in a bento box. However, they are much more expensive than the other materials, and they require more care, like thoroughly drying the bento box after washing to prevent deterioriation.

Types & Functions

Now we’ve covered the materials that are commonly used to make bento boxes, we will go over the various types of bento boxes and the functions each of them have. I will explain the pros and cons of each type so it its easier for you to decide which type is best for you.

Basic plastic bento boxes

normal basic boxes

The most common types bento boxes are one of these basic bento boxes made of plastic. They are by far the most inexpensive, and have the most variations in design. Most of these feature a hinged lid with packing, making them leak proof for a moderate amount of liquids. Lets look at the most popular shapes in this category.


These are usually designed to be used for various purposes and not specially made to hold bentos. They are very cheap and useful as most are microwavable and freezable. However, they do have some disadvantages such as being really hard to wash off the grease from the food, the lid being too easy to accidentally open, and having no dividers to separate food from another. Its best to carry these in a lunch bag to prevent it from accidentally opening and spilling. This is the way to go if you’re on a very tight budget and don’t really care so much about the way your bento box looks.

bento system

Lunch Box Systems

These are kind of like premium tupperwares that are specialized for bento lunches. They have different sections divided for different food. They are great for food that are made cool and
dry like sandwiches and fruits, but not designed to handle any type of japanese bento. They come in many color variations, which most of them look like they are for elementary school kids. This could be good if you are going to be making bento for your young kids.

single tier

Single Tier Japanese Bento Box

These are the most common type of bento box you can find in Japan. There are tons and tons of creative designs for this type. They usually have a flat bottom surface, unlike most tupperware. Many of them include a removable divider piece inside the bento box to keep the juicy food from touching the rice. Some have a slot to place chopsticks in. A square wrapping cloth called “furoshiki” is often used to keep the bento box tightly sealed.


Two Tier Japanese Bento box

These are the types that have two separate containers that stack on top of each other. One container is for rice, and another is for the other food. Its better to use this type when you are packing runny food to avoid the rice being soaked in its juice. Two tier bento boxes often can hold slightly more food that single tier bento boxes. Other than that subtle difference, they can basically be treated the same way as a single tier Japanese bento box.

The Pros and Cons of Basic Plastic Bento Boxes


  • inexpensive
  • many variations in design
  • many are microwavable
  • many are dishwasher safe
  • many are leak proof


  • hard to remove the grease
  • hard to remove the stains
  • hard to remove smell
  • not long lasting

Heat retaining (Insulated) Bento Boxes

retaining bento boxes

Most food tastes better when they’re hot, right? If you use a heat retaining bento box, you can pack your bento in the morning while the food is still hot, and it will still be warm when you eat it at lunchtime. But wait. There are a few things that you need to know before you get all excited and order your insulated bento box on amazon. When you hear “heat retaining bento box”, you would probably imagine your bento being hot and steamy when you open it at your office. But the reality is not that glorious. First, let me explain what a heat retaining bento box really is.

Insulated bento boxes means that there is a heat retaining function in the bento box, but that doesn’t necessarily apply to the entire bento box. In fact, most of these bento boxes only keep a part of the bento box warm. This is because some foods cannot be kept warm for a long time without going bad. There are a couple of types of heat retaining bento boxes, and they are each designed to specialize in a different kind of lunch meal.

heat retainer bento box

Partial Heat Retainer

The rice bowl part of the bento box is structured to insulate the heat, and the bowl for the other foods are just normal without any special features. You will need to pack your dishes and wait until its cooled before closing the lid, and then pack your steamy rice in the insulated bowl.

lunch jar

Lunch Jar Type

These feature one big stainless heat retaining jar type case that you put three or four separate containers in, including a bowl for soup. The soup container and the rice container usually are the only ones that are designed to retain heat. The soup bowl goes in the very bottom, and then the rice bowl goes on top of that, and then the main dish bowl on top of that. Because the whole jar is insulated, the heat of the soup will keep the rice warm for a longer time.

soup jar

Soup Jar Type

These are specialized in carrying soup or stew for lunch. They keep the soup warm with its vacuum insulation. There are many recipes specially written for these soup jars, which you just put raw ingredients in the jar in the morning, and by lunchtime, the heat will have cooked the food and they will be good for eating. Amazing, right?

How warm can they actually keep the food?

Each bento box manufacturer have their heat retaining level written on the product box. For example, Thermos writes on each product the temperature of water after being sealed in its product for 6 hours starting with a temperature of 95 degrees celsius in a room of 20 degrees celsius. Although those numbers are good as a general reference, the actual things we put in the insulated bento boxes is probably not water, but rice and or soup. It is better to assume that the food will be lower in temperature than what the manufacturer says.

Realistically, you would be packing rice that is about 70 degrees and after 5 or 6 hours, eat it in about 40 to 50 degrees warmth. This is not steaming hot, but warmer than “luke warm”. This still can be a major difference in contrast to eating a very cold bento.

How to keep your bento warm for longer

As I wrote above, insulated bento boxes don’t necessarily keep your food warm enough to the point of your satisfaction. You will need to implement these tips to keep your bento warmer. The key is residual heat. Before you pack your bento, pour in some boiling water in to the insulated jar, and also in your rice bowl. This will heat the container, preventing it from cooling down the food you pack. It will give the entire bento box residual heat and you can start off the temperature decline from a much higher place, which will greatly help your food to stay warm until lunchtime.

Be cautious of food poisoning

Heat retaining bento boxes is a great invention for sure, but there is a point that you really need to know. It is that some food will go bad very fast in lukewarm temperature. When using a insulated bento box, you must take care to prevent your food from going bad. For a normal bento, you will have to cool down both the rice and the side dishes before closing the lid. This is to avoid food poisoning. When the food temperature is around 40 degrees celsius, this is when bacteria will be most active multiplying. Rice alone would not have as big of a problem, but other food can be very damaged. It is best to only pack the rice in the heat retaining bowl.

The Pros and Cons of Heat Retaining Bento Boxes


  • you can keep you food warm
  • you can carry liquid food like soup
  • durable


  • heavy in weight
  • larger in size
  • relatively expensive
  • some have many pieces to wash

Bentwood Bento Boxes

bentwood bento boxes

Recent bento boxes are becoming more and more high tech with awesome features as heat retaining, but on the other hand, old school bento boxes made of wood are also gaining popularity, especially the bentwood bento boxes made of natural materials. Bentwood bento boxes is made of thin board of Japanese cedar or cypress bent in to a round shape. They are made in many parts of japan as traditional crafts. So why are they still popular? Its because its ability to keep the rice tasty. The wood actually absorbs some of the moisture that comes out of the rice, keeping the rice taste delicious even when its cold. It also helps to keep the rice from going bad in the summertime, and keeping it from hardening in the wintertime, making it a year-round excellent performer. There is a couple of ways a bentwood bento boxes are coated in, an each coating changes the features of the bento box.

uncoated wood


You will be able to enjoy the goodness of bentwood to the fullest with the unpainted and uncoated bento boxes. You will be able to enjoy the wonderful smell of wood, and its absorption of moist making your rice taste great even when its cold. However, the lifespan of these bentoboxes are pretty short, and are also weak to grease. Not only that, but you will have to have it completely dry before use. It needs much more care and maintenance compared to other coated bentwood bentoboxes.

lacquer coated

Lacquer Coated

Lacquer coated bentwood bento boxes are much easier to handle than uncoated ones. Not only can you
use neutral detergent to wash them, but by wiping them with a dry cloth, you can enjoy how the polish changes expressions day by day. Lacquer itself has a bactericidal feature making laquer coated bento boxes relatively safe. Although they don’t absorb as much moisture as a uncoated bento box, you will still be able to taste some difference in taste.

urethane coated

Urethane Coated

urethane coated bentwood bento boxes are most resistant to grease and requires less maintenance for use. But you will not be able to smell the wood, and it will not absorb any moisture from the rice either. Most urethane coated bentoboxes are more affordable than the other two types, so its nice if you just like its shape and the way it looks but not willing to put in the time to take extra care of it.

Can you microwave bentwood bento boxes?

Easy answer to this is, no. Especially for the lacquer coated models, the coating will shrink due to radical change in temperature causing them to crack. Even if your bentwood is not lacquer coated, microwaving natural material may cause some deformation. However, in Japan, there have been some new types of bentwood bento boxes that are microwave safe. Hopefully, those will make it to the overseas market as well.

How to take care of your bentwood bento box

bentwood bentoboxes are great as they keep the rice delicious, but in order to use them for a long period of time, it is vital that you properly handle them with care. The correct way to wash bentwood bento boxes vary slightly depending on how its coated. for example, most uncoated models are recommended not to use any neutral detergent. First, you should immerse the bento box in water to remove the pieces of food that are stuck to the surface. After a few minutes, you should be able to easily wipe off the dirt from the surface. Use a sponge to clean it gently. After that, place the bento box upside down in a dry area, and then when the water is cleared from the inside, turn it over and dry it with the lid side up. The reason that you have to keep it upside down first is because if there is water left in the corners of the bento box, that may cause the bento box to deform. This is all it takes to wash a bentwood bento box. Do not scrub it too hard with the sponge and try to remove all stains from the wood. Some of the stains just can’t be helped, but you can take it as one of the great things about these bento boxes. If you don’t want any stains on your wooden bento box, you should go with coated products.

The Pros and Cons of Bentwood Bento Boxes


  • rice tastes awesome
  • looks great


  • requires good care
  • not microwavable
  • expensive
  • not leak proof
  • not dishwasher safe

Characteristics of Aluminum Bento Boxes

aluminum bento boxes

In Japan, aluminium bento boxes used to be the most popular type of bento boxes for all ages. However, in the recent years things have been changing rapidly and less and less people are using aluminum lunch boxes and are switching to heat retaining bento boxes, or bentwood bento boxes.

Tips on how to keep the rice from sticking to the surface

Everyone who has an aluminum bento box has probably experienced rice sticking to the surface making it pretty hard to scrape it off with chop sticks. You can prevent this from happening by coating the inside of your bento box lightly with olive oil or butter before you pack the rice. This way, you will have no problem eating your rice!

The Pros and Cons of Aluminum Bento Boxes


  • lightweight
  • robust
  • long lasting
  • easy to open even for little kids


  • nor leak proof
  • rice sticks to the surface easily
  • very few variations in design
  • not microwavable
  • cannot use bleaching agent
  • not dishwasher safe

Characteristics of Stainless Steel Bento Boxes

aluminun bento boxes

Another typical type of Japanese bento boxes are stainless bento boxes. These are very durable and hard to break, and its biggest feature is how well it keeps itself free of smell or stain from the food. Even with the emerging popularity of heat retaining bento boxes, stainless bento boxes is keeping is firm position in popularity.

The Pros and Cons of Stainless Steel Bento Boxes


  • very robust
  • long lasting
  • resistant to smell
  • resistant to stains
  • easy to wash
  • many are leak proof
  • many are dishwasher safe


  • relatively expensive
  • not microwavable
  • very few variations in design

Characteristics of Dabba Type Bento box


Japan is not the only country that has a long history of carrying bentos. In India, people have been using special bento boxes called “dabba”. There is a major difference in the culture though. Its that in India, instead of packing their bento in the morning and carrying to work, they have their dabba delivered by specialized men called dabbawalla from their family just before lunch time.

Dabbas usually comes in a cylinder shape, with 2-4 bowls stacked on top of each other. They are commonly made with stainless steel, and are very robust. It is not easy to break them, and they are probably the most strongest type of bento box there is on the market. And because the entire dabba is made of stainless steel, you have the advantage of sterilizing it by immersing it in boiling water.

The Pros and Cons of Dabba


  • very robust
  • resistant to smell
  • resistant to stains
  • easy to sterilize


  • not leak proof
  • not microwavable
  • very few variations in design