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New Trip Editorial Department Last updated: 2026.06.25

A guide to choosing the right suitcase size: The first step to making travel easier

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Good morning, fellow travel lovers! Have you ever made a mistake choosing the right size suitcase ? I had a bitter experience trying to get through a three-night stay with a small-size suitcase, but it didn't fit a bottle of wine I brought home as a souvenir, so I had to carry it all by hand.

To avoid such tragedies, today we'll be explaining the basics of suitcase sizes ! We'll be digging deeper into S, M, and L sizes in this series, so let's get the big picture straight away. Let's get started on the first step to making your trip easier!

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table of contents

1. Suitcase sizes, types and features

2. Carry-on and checked baggage size restrictions

2. Tips for choosing a suitcase depending on the number of days you are traveling

3. Common mistakes when choosing suitcase size and how to avoid them

4. Tips for choosing the right suitcase size for each occasion

summary

七、まとめ

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一、スーツケースサイズの目安と選び方【泊数別早見表】

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Suitcases come in three main sizes : S, M, and L. They're divided like clothing sizes, which is simple, but knowing the characteristics of each will make it easier to choose.

宿泊日数	容量目安	サイズ目安	おすすめシーン
日帰り〜1泊	～25L	SSサイズ	出張・イベント・ジム・近場の旅行
1〜2泊	25〜35L	Sサイズ	国内旅行・短期出張
2泊3日	30〜45L	S〜Mサイズ	週末旅行・荷物多めの国内旅行
3泊4日〜5泊	45〜60L	Mサイズ	修学旅行・短期海外旅行
5〜7泊	60〜80L	M〜Lサイズ	1週間前後の海外旅行・冬の旅行
7泊以上	80〜100L	Lサイズ	長期旅行・家族旅行

Height within 55cm ( including wheels and handles ), capacity approximately 20-40L .

It's perfect for short trips of 1-3 nights , and its biggest appeal is that it can be carried on board .

The best thing about it is being able to move around freely without the hassle of checking it in.

Once, my checked luggage was delayed in Europe, and I had to wait in the lobby on my first day, and ever since then I've been hooked on the convenience of the small size.

・New Trip Suitcase S size

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二、泊数だけでは足りない？荷物量でサイズを調整する

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When using a suitcase on an airplane, in addition to capacity, you need to check the "total dimensions (length + width + height)" and "weight limit."

However, rules vary depending on the airline, route, and seat class, so always check the latest information before your departure.

冬服・厚手の衣類が多い

Carry-on suitcase sizes are generally considered to be within 115 cm for the total outer dimensions of three sides. (If the aircraft has fewer than 100 seats, it's usually within 100 cm total.)

While ANA and JAL often have a weight limit of 10 kg, low-cost carriers (LCCs) may have stricter weight restrictions, such as 7 kg.

If you prioritize carry-on, check not only the capacity but also the weight of the suitcase itself. If the suitcase itself is heavy, you might exceed the weight limit with only a small amount of luggage inside.

靴や洗面用品など、かさばる荷物が多い

For checked suitcases, a general guideline for free baggage is a total of 158 cm for the sum of the three dimensions.

If you choose an L or LL size, you may incur additional charges if the external dimensions are too large, even if the capacity is sufficient.

Also, for international travel, a weight limit of 23kg is a common guideline.

Pay attention not only to the size but also to the weight, especially if you pack a lot of winter clothes, shoes, and souvenirs.

お土産を持ち帰る

行きは十分でも、帰りにお土産が増えて荷物が入らなくなることがあります。
特に海外旅行では、お土産を買う前提でワンサイズ上、または拡張機能付きモデルを選ぶと安心です。

PC・仕事道具を持って行く

ノートPCやタブレット、充電器、書類など、仕事道具を持参する場合は、
重量は増えなくても収納スペースが必要になります。
フロントオープン付きモデルなら、移動中に取り出しやすくなります。

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まとめ： 泊数別の容量はあくまで目安。荷物が多い人は、1サイズ上を検討しましょう。

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三、移動方法によって、選びやすいサイズは変わる

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同じ容量でも、移動方法によって扱いやすさが変わります。飛行機・新幹線・車など、主な移動手段に合わせて確認しましょう。

飛行機を利用する場合

区分	サイズ目安	重量目安
機内持ち込み	3辺合計115cm以内	10kg以内が目安
無料預け入れ	3辺合計158cm以内	23kg以内が目安
LCC利用	航空会社ごとに異なる	7kg前後が多い

飛行機では、機内持ち込みにするか、預け入れるかで選ぶべきサイズが変わります。

機内持ち込みサイズ

　一般的に、3辺の合計が115cm以内、重量7〜10kg以内が目安です。
　ただし、航空会社や機材によって規定が異なるため、搭乗前に公式サイトで確認しましょう。

Sサイズ：機内持ち込み候補
M・Lサイズ：基本的に預け入れ

預け入れる場合

　預け入れ荷物のサイズ・重量制限も、航空会社や運賃プランによって異なります。

　LCCでは追加料金が発生する場合もあるため、事前確認が大切です。

新幹線・電車を利用する場合

新幹線や電車では、車内での扱いやすさが重要です。

荷物置き場を利用する場合

　座席上の荷物棚や車両端の荷物置き場を利用できます。
　ただし、混雑時は置けないこともあるため、Sサイズの方が安心です。

足元に置く場合

　MサイズやLサイズを足元に置く場合、座席スペースが狭くなります。
　キャスターストッパー付きモデルなら、停車中に転がるのを防げます。

車で移動する場合

車移動では、トランクや車載スペースに収まるサイズを確認しましょう。複数人で旅行する場合は、全員分のスーツケースが積めるかも事前に確認が必要です。

車移動なら、持ち運びの頻度が少ないため、大型サイズでも扱いやすくなります。

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四、スーツケースの「サイズ」はどこを見ればいい？正しい測り方

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Choosing a suitcase based on the number of days you will be traveling will have a big impact on the amount of luggage you will have and how convenient it will be to travel.

This chapter will give you tips on choosing the best size and type for the length of your trip.

確認項目	チェックポイント
高さ	キャスター下からハンドル上部まで測る
幅	サイドハンドルなど突起部を含める
奥行き	拡張機能を使った状態も確認する
3辺合計	高さ＋幅＋奥行きで計算する

商品ページの外寸と本体寸法の違い

On product pages for suitcases, you may sometimes find "body dimensions" and "overall dimensions" or "total external dimensions" listed separately. Since airlines often check the total size, including wheels and handles, when considering carry-on or checked luggage, it's best to use the total external dimensions as your guide.

There have been cases where a suitcase's "body alone was within 55cm, but when including the wheels, it exceeded the size limit." Especially when choosing a carry-on suitcase, it's crucial to confirm that the sum of its three sides is within 115cm.

3辺合計の計算方法

Suitcases with an expandable function, which allows you to increase their capacity, are convenient when you have more souvenirs after a trip. However, opening the zipper to expand them increases their depth, and the sum of their three dimensions may change.

For example, even if a suitcase is within carry-on size before expansion, if the sum of its three dimensions exceeds 115cm after expansion, it may not be allowed as a carry-on. If you plan to use it as a carry-on, be sure to check the external dimensions not only before but also after expansion.

In the case of the "New Trip 0201 Plus," the depth increases by approximately 4.5cm after expansion, and the total external dimensions change from approximately 114cm to approximately 118.5cm.

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五、New Tripのサイズ別おすすめモデル

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Choosing the right size suitcase for your travel needs will greatly improve your comfort.

This chapter introduces the optimal sizes for different purposes.

For business travel , a compact suitcase (30-40L) that can be carried on board is ideal. It allows for smooth travel and is convenient for carrying business documents and a laptop.

・Family travel : You will need a suitcase with a large capacity (60L or more). Focus on storage capacity so that you can store clothes and items for the whole family.

For solo travelers and backpackers : A lightweight suitcase (40-50L) is ideal for those who want to travel light and with minimal luggage. Its flexibility and ability to move around easily are its main advantages.

By choosing the perfect size for your travel needs, you can easily organize your luggage and travel smoothly.

Sサイズ｜1〜3泊の旅行に

For domestic trips of 1-3 nights or short business trips, an S size suitcase of around 30-40L is recommended. This size is easy to carry on airplanes and convenient to handle when traveling by train or Shinkansen.

If you frequently move between stations, it's convenient to choose a size that fits easily into coin lockers, or a model with caster stoppers.

New Trip 0702Plus スーツケース

約42L｜ABS+PC

コインロッカー対応サイズ TSA008ロックフロントオープンキャスターストッパー

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Mサイズ｜3〜7泊の旅行に

For trips lasting 4 to 7 nights, an M-sized suitcase with a capacity of around 50-70L is a convenient choice. It offers ample space for clothes, toiletries, and souvenirs, making it suitable for both domestic and international travel.

If you're buying your first suitcase or are unsure between an M and L size, starting with an M-sized one is often the easiest option to manage.

New Trip 0201

Mサイズ・60L｜ABS+PC

超軽量3.6kg 拡張機能 TSAロックコーナーパッド

商品を見る

Lサイズ｜7泊以上・長期滞在に

For trips lasting 7 nights or longer, or family trips, a large size over 80L is suitable. This size makes it easy to pack winter clothes or luggage for multiple people, and is also convenient for trips where you plan to buy many souvenirs.

However, note that large suitcases tend to be heavy, so be sure to check that it does not exceed the checked baggage limits of 158cm total linear dimensions or 23kg in weight. For trips involving a lot of movement, it may be easier to handle multiple M-sized suitcases rather than consolidating everything into one large suitcase.

New Trip 0502

Lサイズ・100L｜PC素材+亜鉛合金コーナーパット

HINOMOTO製静音キャスター拡張機能 TSAロック防水ポケットスマホスタンド

商品を見る

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六、よくある質問（FAQ）

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Q1. 3泊4日の旅行には何Lのスーツケースが必要ですか？

A1：一般的には40〜60L前後のMサイズが目安です。ただし、冬の旅行や荷物が多い場合は、ワンサイズ上を検討しましょう。

Q2. 機内持ち込みサイズは何Lまでですか？

A2：航空会社によって異なりますが、30〜40L前後のSサイズが目安です。3辺合計が115cm以内、重量7〜10kg以内が一般的です。

Q3. スーツケースのサイズはどこを測ればいいですか？

A3：キャスターを含めた外寸（縦×横×高さ）を確認してください。航空会社の規定を確認する際は、3辺合計も計算しましょう。

Q4. 荷物が増えやすい場合、どのサイズを選べばいいですか？

A4：泊数別の目安よりワンサイズ上、または拡張機能付きモデルを選ぶと安心です。

Q5. SサイズとMサイズ、どちらを選ぶか迷っています。

A5：1〜3泊の旅行が多いならSサイズ、3〜5泊の旅行が多いならMサイズがおすすめです。迷った場合は、Mサイズを選ぶと幅広い旅行に対応できます。

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七、まとめ

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This time we've introduced the basics of suitcase sizes . What did you think? S, M, and L each have their own appeal, and it's interesting to see how your choice changes depending on your travel style.

We'll be looking at each size in detail from now on, and next time we'll be giving a thorough explanation of the " S size "! I'll also be sharing tips for carry-on luggage, my favorite recommended models, and "packing techniques for getting through a three-night stay in an S size." Please look forward to it.

What size are you? Let us know in the comments. See you next time!

執筆・監修

New Trip編集部
本記事は、スーツケース・旅行用品ブランド「New Trip」の編集部により制作されました。
製品開発やユーザーの声を活かしながら、ユーザーに合ったスーツケースや、旅行・出張をより快適にするアイテムを発信しています。

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