Grammar Rule in 30 Seconds
Use 'will' for sudden decisions and 'going to' for plans you made before speaking.
- Use 'will' for spontaneous choices: 'I'll have the coffee.'
- Use 'going to' for prior plans: 'I'm going to visit Paris next month.'
- Use 'going to' for predictions with evidence: 'Look at those clouds! It's going to rain.'
Overview
will と be going to には、ちょっとした、でも厄介な違いがあるんだ。多くの学習者は何でも will を使っちゃう。楽だしね。でも、使い方を間違えるとロボットみたいに聞こえたり、計画性がない人だと思われちゃうかも。昨日が締め切りだったレポートについて、上司に I will finish the report（今から終わらせます）なんて言っちゃうところを想像してみて。今この瞬間に思いついたみたいに聞こえちゃうんだ。おっと。will と be going to を使い分けるよ。will は反応が早い、ノリのいい友達。be going to はきっちり計画を立てる、しっかり者の友達。どちらも未来を見ているけど、世界の捉え方が違うんだ。このルールを覚えれば、話すときもメールするときも、いつも正しい方を選べるようになるよ。How This Grammar Works
will を使う。スイッチが「昨日」すでに入っていたなら、be going to を使う。これが未来の意志に関する黄金ルールだよ。予測をするときにもこれらを使うよ。黒い雲を見て It's going to rain（雨が降りそうだ）と言うなら、そこには根拠があるよね。でも I think humans will live on Mars（人類は火星に住むと思う）と言うなら、それはただの推測。お天気アプリと水晶玉の違いみたいなものかな。一方は事実に基づいていて、もう一方は直感（バイブス）なんだ。
Formation Pattern
will の場合は、動詞の原形の前に置くだけ。
be going to の場合は、be の部分を変える必要がある。
am、is、are を使い分けよう。
going to はよく gonna（ガナ）って聞こえるよ。ただ、失業したくないなら、仕事の応募書類に gonna って書いちゃダメだよ！
When To Use It
will を使おう。カフェで店員さんに注文を聞かれたとき、君は I'll have a latte, please（ラテをください）と言うよね。3日前からそのラテを計画していたわけじゃないはず。約束をするときも will を使うよ。I'll always love you（ずっと愛してる）の方が、I am going to love you よりも響きがいいんだ。前者は心のこもった誓いだけど、後者はカレンダーに予定されたタスクみたいに聞こえちゃう。be going to を使おう。ロンドン行きの飛行機を予約したなら、I'm going to London と言おう。もし I'll go to London と言うと、もっと楽しそうなパーティーの誘いがあったら予定を変えちゃうかも、みたいに聞こえるんだ。今目の前で見えていることに基づいた予測にもこれを使おう。スマホのバッテリーが1%なら、My phone is going to die（スマホの充電が切れそう）と言う。画面に証拠が見えているからね。
Common Mistakes
will を使わないようにね。午後2時にZoom会議があるなら、I will meet them at 2 とは言わない。突然思いついたみたいに聞こえるからね。代わりに I'm going to meet them と言おう。もう一つの間違いは、going to の am/is/are を忘れちゃうこと。I going to eat はよくある間違い。これだと原始人みたいに聞こえちゃう。I am going to eat の方がずっといいね。最後に、物理的な証拠があって、すぐにも起こりそうなことには will を使わないようにしよう。棚の上で花瓶がガタガタ揺れているなら、It's going to fall!（落ちる！）と言おう。It will fall ではないよ。後者はまるで魔法使いの呪いみたいに聞こえちゃうから。Contrast With Similar Patterns
I'm meeting Sam tonight（今夜サムと会うんだ）。これは going to よりもさらに確実性が高い。時間も場所もGoogleカレンダーにセット済みって感じ。I'm going to meet Sam は計画だけど、まだレストランは決めていないかもしれない。I'll meet Sam は、サムから突然電話がかかってきて「遊ぼうよ」と言われたときに使う言葉。これは確信度のスペクトラム（連続体）なんだ。Quick FAQ
天気について will を使ってもいい？
うん、一般的な予測をするならOK。It will be cold in winter（冬は寒くなるよ）みたいにね。
gonna を使っても大丈夫？
友達と話したりメールしたりするときは、もちろん！フォーマルなメールでは避けようね。
will の否定形は何？
won't だよ。will not の短縮形で、こっちの方がずっと自然に聞こえるよ。
一つの文章で両方使ってもいいの？
もちろん！I'm going to go to the store, and I'll buy some milk while I'm there（店に行くつもりだから、ついでに牛乳も買ってくるよ）。店に行くのは計画（going to）で、牛乳を買うのはその場で思いついたこと（will）だね。
Future Forms Conjugation
| Subject | Will Form | Going To Form | Negative (Will) | Negative (Going To) |
|---|---|---|---|---|
|
I
|
will work
|
am going to work
|
won't work
|
am not going to work
|
|
You
|
will work
|
are going to work
|
won't work
|
aren't going to work
|
|
He/She/It
|
will work
|
is going to work
|
won't work
|
isn't going to work
|
|
We
|
will work
|
are going to work
|
won't work
|
aren't going to work
|
|
They
|
will work
|
are going to work
|
won't work
|
aren't going to work
|
Common Contractions
| Full Form | Contraction | Example |
|---|---|---|
|
I will
|
I'll
|
I'll help you.
|
|
You will
|
You'll
|
You'll see.
|
|
He will
|
He'll
|
He'll be there.
|
|
She will
|
She'll
|
She'll arrive soon.
|
|
We will
|
We'll
|
We'll win.
|
|
They will
|
They'll
|
They'll call.
|
|
Will not
|
Won't
|
I won't go.
|
|
Going to (Spoken)
|
Gonna
|
I'm gonna go.
|
Meanings
English uses different structures to talk about the future depending on whether we are predicting, planning, or deciding in the moment.
Spontaneous Decisions
Deciding to do something at the exact moment of speaking.
“The phone is ringing. I'll get it!”
“I'm tired. I think I'll go to bed now.”
Prior Plans and Intentions
Something you have already decided to do before the conversation started.
“We are going to get married in June.”
“I'm going to start a new job on Monday.”
Predictions based on Evidence
Predicting the future because of something we can see or feel right now.
“Watch out! You're going to drop that vase!”
“I feel terrible. I think I'm going to be sick.”
Predictions based on Opinion
Predicting what we think or believe will happen, without physical evidence.
“I'm sure you will pass the exam.”
“People will live on Mars one day.”
Promises and Offers
Using 'will' to commit to an action for someone else.
“I will always love you.”
“I won't tell anyone your secret.”
Reference Table
| 状況 | どちらを使う？ | 理由 | 現代の例文 |
|---|---|---|---|
|
急な決定
|
Will
|
今決めたこと
|
I'll like this photo.
|
|
前からの計画
|
Going to
|
前に決めていたこと
|
I'm going to post a Reel.
|
|
予測（証拠あり）
|
Going to
|
起こるのが見えている
|
He's going to lose the game.
|
|
予測（意見）
|
Will
|
起こると思う
|
AI will take over the world.
|
|
約束・申し出
|
Will
|
手伝いを申し出る
|
I'll Venmo you the money.
|
|
拒否
|
Won't
|
することの拒否
|
My phone won't charge!
|
フォーマル度スペクトル
I shall depart at six o'clock. (Departure)
I am going to leave at six. (Departure)
I'm gonna head out at six. (Departure)
I'm outtie at six. (Departure)
未来形の全体像
Will（瞬発的）
- 決定 I'll buy it!
- 約束 I'll call you.
Going To（計画的）
- 意図 I'm going to travel.
- 証拠 It's going to rain.
Will vs. Going To 比較表
どちらを使えばいい？フローチャート
今、決めたことですか？
計画や証拠はありますか？
よくあるシチュエーション
カフェ・注文
- • I'll have a coffee.
- • I'll take the bill.
カレンダー・旅行
- • I'm going to fly to Paris.
- • We're going to meet at 5.
レベル別の例文
I will call you later.
I am going to watch TV.
It will be sunny tomorrow.
Are you going to eat?
I'll have the blue shirt, please.
She is going to study medicine next year.
Look! The bus is going to leave!
I won't tell your secret to anyone.
I think the government will raise taxes soon.
We're going to have a barbecue if the weather stays nice.
I'll just check my diary and let you know.
Is it going to be a difficult meeting?
The company will be launching its new product in May.
I was going to buy that car, but I changed my mind.
If you don't hurry, we're going to miss the start.
You'll find that most people are very friendly here.
The Prime Minister will address the nation at 8 PM.
He's going to be a handful when he grows up!
Will you be staying for dinner, or must you head off?
It's going to take more than a miracle to fix this.
Boys will be boys, I suppose.
The structural integrity is going to be compromised if we proceed.
Whatever will be, will be.
She will insist on doing everything herself.
間違えやすい
Both talk about the future. Learners don't know which is 'more' planned.
Both are used for predictions.
よくある間違い
I will to go.
I will go.
I going to eat.
I am going to eat.
She wills help.
She will help.
I will go to Paris next year (already booked).
I am going to go to Paris next year.
It will rain! (looking at black clouds)
It is going to rain!
I'll meeting you at 5.
I'll meet you at 5.
Are you will come?
Will you come?
I'm going to will go.
I'm going to go.
I will probably to be late.
I will probably be late.
I shall to do it.
I shall do it.
文型パターン
I think I will ___.
I am going to ___ next week.
Look! That ___ is going to ___!
Don't worry, I won't ___.
Real World Usage
I'll have the burger, please.
I'm gonna be 5 mins late!
It will be a cold start to the day.
I will contribute to the team's success.
We are going to visit the museum at 10.
Watch out! You're going to trip!
「今すぐ」テスト
予定が決まっている場合は「will」を避けて
「証拠」のルール
Smart Tips
Always use 'I'll have...' rather than 'I'm going to have...'. It sounds more decisive and natural to the waiter.
Use 'going to'. If you see a person running very fast toward a door, say 'He's going to open the door'.
Use 'will' to show commitment. 'I will help you' sounds like a stronger promise than 'I am going to help you'.
Avoid 'gonna' and even 'I'll'. Write out 'I will' or 'We are going to' to maintain a professional tone.
発音
Contraction of Will
The 'll' sound is often a 'dark L'. It sounds like a small 'ul' sound at the back of the throat.
Gonna
In fast speech, 'going to' becomes 'gonna'. The 'to' sound disappears completely.
Spontaneous Will
I'll ↗ GET it!
Emphasis on the action decided suddenly.
Going To Prediction
It's going to ↘ RAIN.
Falling intonation on the final word for a statement of fact/evidence.
暗記しよう
記憶術
Will is for the 'Wheel' of fortune (luck/spontaneous), Going To is for the 'Goal' (planned).
視覚的連想
Imagine a lightbulb turning on for 'Will' (a sudden idea). Imagine a calendar with a circled date for 'Going To' (a plan).
Rhyme
If you plan it in your head, 'Going To' is what is said. If you decide it on the spot, 'Will' is what you've got!
Story
A man sees a woman struggling with a suitcase. He thinks, 'I'll help her!' (Will - spontaneous). Later, he tells his wife, 'I'm going to buy a new suitcase for our trip' (Going to - plan).
Word Web
チャレンジ
Look around the room. Find one thing that is 'going to' happen (e.g., a candle burning out) and make one 'will' decision (e.g., 'I'll drink some water').
文化メモ
British speakers may use 'shall' for offers ('Shall I open the window?'), whereas Americans almost always use 'should' or 'will'.
The use of 'gonna' is extremely prevalent in all but the most formal spoken contexts. Using 'going to' in a casual bar might sound slightly stiff.
Using 'will' for a promise is culturally significant. 'I will' is the standard response in marriage ceremonies.
'Will' comes from Old English 'willan' (to wish/want). 'Going to' developed later as a way to use a verb of movement to show a path toward a future action.
会話のきっかけ
What are you going to do this weekend?
I'm thirsty. What will you drink?
Where do you think you will be in five years?
Look at the economy. What's going to happen next?
日記のテーマ
よくある間違い
Test Yourself
You see a friend carrying a lot of books. You say:
We ___ (travel) to Japan next summer. We already bought the tickets!
Find and fix the mistake:
Look! That car will crash into the wall!
Score: /3
練習問題
8 exercisesThe phone is ringing. ___ answer it.
We ___ (visit) our grandparents this weekend.
Find and fix the mistake:
Look! That car will hit the wall!
not / I / tell / will / anyone / .
1. Sudden decision, 2. Prior plan, 3. Evidence prediction
A: Why are you holding that bucket? B: I ___ wash the car.
You can use 'will' for a plan you made yesterday.
I am going to carry your bags. (Change to 'will')
Score: /8
Practice Bank
10 exercisesI'm hungry. I think I ___ make a sandwich.
Choose the correct sentence:
She will to meet her mom at the airport at 5 PM.
Voy a estudiar medicina el próximo año.
the / open / I / door / will
Match these:
Watch out! You ___ drop your phone!
You see someone struggling with a door.
Are you will go to the party?
No te olvidaré.
Score: /10
よくある質問 (8)
Sometimes, especially for general predictions like 'It will rain' vs 'It's going to rain'. However, for plans vs. spontaneous decisions, they are not interchangeable.
It is a phonetic spelling of how people speak. It is not used in formal writing, but it is very common in songs, movies, and texts.
English is a stress-timed language. We prefer to contract unstressed words like 'will' to keep the rhythm of the sentence.
If you are in doubt, 'going to' is often safer for personal intentions, while 'will' is safer for general facts.
Yes, always. Without the 'be' verb, the sentence is grammatically incomplete.
Yes, for general predictions ('It will be cold in winter'). Use 'going to' if you see clouds right now.
In modern English, 'shall' is mostly used for polite suggestions ('Shall we dance?') or very formal documents.
Move the 'be' verb to the front: 'Are you going to...?'
Scaffolded Practice
1
2
3
4
Mastery Progress
Needs Practice
Improving
Strong
Mastered
In Other Languages
Futuro Simple vs. Ir a + infinitivo
English 'will' is strictly for spontaneous/promises, whereas Spanish 'futuro' can be more formal.
Futur Simple vs. Futur Proche
French uses Futur Proche more frequently in conversation than English uses 'going to'.
Präsens vs. Futur I
English requires a future marker (will/going to) much more often than German does.
Dictionary form + tsumori / yotei
English uses auxiliary verbs (will) while Japanese uses sentence-ending nouns or particles.
Sa- / Sawfa + Present Verb
The Arabic distinction is based on time distance, while English is based on the nature of the decision.
Yào (要) / Huì (会)
Chinese verbs never change form; the meaning comes entirely from these helper words.
Learning Path
Prerequisites
Learn These First
関連動画
05:30 Dwight vs. the Computer - The Office
07:11 Talking About Expected Results
16:59 Learning to code has changed
Learn All 12 English Verb Tenses | Complete English Grammar Lesson
JForrest English
MASTER ENGLISH VERB TENSES — All 12 Tenses Explained in 20 Minutes (Complete Guide)
English At The Ready
English Verb Tenses Guide - Learn About Simple, Perfect, and Continuous Tenses
Oxford Online English
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