The Plain Volitional Form ～よう / ～おう: How to Say "Let's" and "I Will" in Japanese

The plain volitional form ～よう / ～おう is the casual way to say "let's do X" or to resolve "I'll do it." It is built from a verb's group.¹ Its polite counterpart is ～ましょう; this page covers the plain form and points to the polite one for the -masu register.

Overview

The volitional expresses the speaker's will, resolve, or proposal. Learners use it to invite a friend, state their own resolve, or frame a plan as an intention, all in casual speech among peers and in-group members.¹²

Three points make the form worth learning carefully. The お-column shift for 五段 verbs is fully derivable once the mechanics are clear, the plain form must not be aimed at a superior, and the same ending feeds several higher-level patterns. Each point is covered below.

What the Volitional Form Is

The volitional is a mood, not a tense. It encodes the speaker's will or proposal rather than placing an event in time. The verb keeps its own non-past and past tense system, separate from this mood.¹

Its Japanese grammatical name is 意向形 (ikō-kei, "intention form"). In English, it is called the volitional or the hortative. The older term 意志形 (ishi-kei, "will form") names the same paradigm.³

The volitional split off from an older "maybe" meaning

The modern volitional descends from the classical auxiliary む (mu), which once carried both conjecture ("probably") and volition ("let's / I shall"). In modern Japanese, those senses split: ～よう / ～おう kept the volitional meaning, while だろう / でしょう took over conjecture.⁴

Where it sits in tense, aspect, and mood

A mood is a grammatical category that marks the speaker's stance toward an action. Here, it marks their intention to bring the action about. The volitional sits alongside the indicative plain forms and the conjecture forms, not inside the tense system.¹

Because it is a mood, not a future tense, ～よう never works as a neutral prediction. We revisit that distinction below.

Plain vs. polite at a glance

～よう / ～おう and ～ましょう express the same content. They differ only in register: the plain form is casual, the polite form carries -masu politeness.²³

The plain form belongs to peers and close in-group members. The polite ～ましょう is the appropriate choice for suggestions and offers directed at strangers, customers, or anyone above the speaker's social rank.²³

Form	Register	Typical addressee
～よう / ～おう	plain / casual	friends, family, close peers, oneself2
～ましょう	polite	strangers, customers, superiors, formal settings23

For the full treatment of ～ましょう, see the polite-volitional article. This page links to it rather than duplicating it.

How to Form the Plain Volitional

Formation depends entirely on the verb group. 一段 verbs take one suffix, 五段 verbs shift their final kana, and the two irregular verbs are memorized.

一段 (ichidan / ru-verbs): drop る, add よう

Remove the final る and attach よう.²³ This is the simplest group, because よう joins the vowel-final stem directly with no kana-row change.⁴

早はやく起おきよう。⁵
"Let's get up early."

今夜こんやはカレーを食たべよう。⁵
"Let's have curry tonight."

その映画えいがを見みよう。⁵
"Let's watch that movie."

五段 (godan / u-verbs): shift the final kana to its お-column, add う

Take the final kana of the dictionary form, move it from its current vowel row to the お-column of the same consonant row, then add う.²³⁶ So く → こ ＋ う, む → も ＋ う, つ → と ＋ う, う → お ＋ う.

The shift is fully regular across every consonant row. You can derive any 五段 volitional instead of memorizing a list: the ending is always an お-row kana plus う.²⁶

Read the ending as one long vowel

The お-row kana plus う is pronounced as a single long /ō/, not as two separate sounds. 行こう is ikō, not iko-u.⁴

一緒いっしょに行いこう。⁵
"Let's go together."

何なにか飲のもう。⁵
"Let's drink something."

もう少すこし待まとう。⁵
"Let's wait a little longer."

今日きょうは早はやく帰かえろう。²
"Let's go home early today."

Irregular: する→しよう, くる→こよう

The two irregular verbs are memorized: する → しよう and くる → こよう.²³

For 来る, the kanji reading shifts from き (as in 来ます, kimasu) to こ in the volitional. So 来よう is read koyō, not kiyō.²³

一緒いっしょに勉強べんきょうしよう。³
"Let's study together."

また明日あしたここに来こよう。⁵
"Let's come here again tomorrow."

Quick-reference conjugation table

Group	Rule	Dictionary form	Volitional	Reading
一段	drop る, add よう	食べる	食べよう	tabeyō
一段	drop る, add よう	見る	見よう	miyō
五段	く → こ + う	行く	行こう	ikō
五段	む → も + う	飲む	飲もう	nomō
五段	つ → と + う	待つ	待とう	matō
五段	う → お + う	買う	買おう	kaō
五段	す → そ + う	話す	話そう	hanasō
五段	る → ろ + う	帰る	帰ろう	kaerō
不規則	memorize	する	しよう	shiyō
不規則	memorize (き→こ)	来る	来よう	koyō

Formation by group is cited to Bunpro² and JLPTsensei.³

What the Volitional Form Means and When to Use It

The plain volitional covers three core uses: inviting someone, resolving on one's own action, and stating an intention with ～ようと思う. They share one form, but they differ in whom, if anyone, the speaker is addressing.

Inviting or suggesting: "let's" / "shall we?"

The most common use is the invitation or proposal sense, matching English "let's …."¹² Adding the question particle か turns the statement into "shall we …?" It explicitly seeks the listener's agreement: 行こうか.²⁶

一緒いっしょに映画えいがを見みに行いこうか。⁵
"Shall we go see a movie together?"

そろそろ食たべようか。⁵
"Shall we eat soon?"

Invitations to a superior need the polite form

This invitation use is for peers and in-group members. When aimed at someone above the speaker's social rank, it is inappropriate; use the polite ～ましょう or a request form instead.²³

Self-resolve and soliloquy: "I'll do it" / talking to yourself

The volitional also expresses the speaker's own resolve, with no second party involved. Used alone, it is a personal decision spoken aloud or thought to oneself.⁷¹

This soliloquy use has no equivalent in English "let's." English renders it as "I'll …" or "I'd better …."⁷

もう寝ねよう。⁵
"I'll go to bed now."

よし、頑張がんばろう。⁵
"Alright, I'll give it my best."

私わたしがカレーを作つくろう。⁶
"I'll make the curry."

Stating an intention with ～ようと思う

Volitional + と思う states the speaker's intention or plan: "I think I'll …," "I'm planning to …."⁸⁹ Because it frames the plan as a thought, it sounds softer and less binding than a flat declaration or つもりだ.⁹

In this pattern と思う reports the speaker's own intention. To report a third party's stated intention, Japanese uses と思っている instead.⁸⁹

来年らいねん、日本にほんへ旅行りょこうしようと思おもう。⁹
"I'm thinking I'll travel to Japan next year."

この本ほんを読よもうと思おもいます。⁹
"I'm thinking I'll read this book."

A dedicated article covers the contrast between と思う, と思っている, and ～つもり, along with the rule against stating others' intentions.

Good to know

Register pitfall: bare ～よう is not for superiors

The bare plain volitional is casual and belongs to peer and in-group speech. Inviting a boss or a teacher with a plain ～よう sounds overly familiar or rude; the polite ～ましょう, or a request form, is the register-appropriate choice.²³

Saying 先生、一緒に行こう ("Teacher, let's go together") to a teacher is the wrong register. Use the polite form instead:

先生せんせい、一緒いっしょに行いきましょう。³
"Teacher, let's go together."

Why 五段 lands on お and 一段 takes よう

The volitional descends from the classical auxiliary む (mu), attached to the 未然形 (irrealis, mizenkei) base. For a 五段 verb, that base is the a-column kana, so 書く gave 書か ＋ む, kakamu. The sequence then underwent the regular Late Middle Japanese change kakamu → kakau → kakō, with /au/ coalescing into the long /ō/ heard today.⁴

That same coalescence helps explain why these verbs are called 五段, "five-row" verbs: the change effectively added an お-row to the inflectional paradigm.⁴

For 一段 verbs, which have a single fixed vowel-final stem, the suffix appears as よう attached directly to that stem (食べ ＋ よう), so no kana-row shift is needed.⁴

A compact way to remember this is: 五段 volitional is historically the irrealis a-row plus む, squeezed into a long /ō/. Seeing it that way explains why the modern ending is an お-row kana plus う, instead of ten separate shift rules to memorize.⁴

Volitional ≠ future tense

The volitional carries the speaker's will or proposal; it is not a neutral prediction. Japanese has no dedicated future tense. A plain non-past or a conjecture form (だろう) handles prediction without volition. ～よう always implies that the speaker wants to act or proposes acting.¹

Saying 明日は雨が降ろう for "it will rain tomorrow" is wrong, because rain is not a volitional agent. Use the conjecture form for the prediction sense:

明日あしたは雨あめが降ふるだろう。⁴
"It will probably rain tomorrow."

"Whether or not" preview: ～ようと

The volitional also feeds higher-level patterns: ～ようとする ("try to / be about to," around JLPT N3) and ～ようが／～ようと ("no matter whether," concessive). This article names them only as concepts. They are taught in their own articles and are not part of the plain-volitional core.

See also

• The Polite Volitional ～ましょう: How to Say "Let's" in Japanese
• Japanese Verb Groups: 一段, 五段, and Irregular
• Tense, Aspect, and Mood in Japanese: A Map
• The Japanese Imperative Form (命令形): Plain Commands and Prohibitions
• The Plain Past た-Form in Japanese: Past, Perfective, and Beyond
• The Masu Form (ます): Polite Present and Future Tense

References

Footnotes

1. Makino, Seiichi, and Michio Tsutsui. A Dictionary of Basic Japanese Grammar. The Japan Times, 1986. Entry "～(y)ō ＜よう／おう＞" (volitional auxiliary). The dictionary glosses the form as the speaker's volition or invitation ("let's," "I'll," "I think I'll") and lists formation off the verb base by group. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷

2. 〜よう・〜おう (Verb[よう]), JLPT N4. Bunpro grammar reference. https://bunpro.jp/grammar_points/%E3%82%88%E3%81%86-%E3%81%8A%E3%81%86. Verb-group formation breakdown, JLPT N4 placement, and the note that plain ～よう/～おう is the casual counterpart of polite ～ましょう. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶

3. 意向形 (ikō-kei) Volitional Form, JLPT N4. JLPTsensei. https://jlptsensei.com/learn-japanese-grammar/%E6%84%8F%E5%90%91%E5%BD%A2-ikou-kei-volitional-form-meaning/. JLPT N4 placement, formation by group, casual-vs-polite register note. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³

4. Frellesvig, Bjarke. A History of the Japanese Language. Cambridge University Press, 2010. Treatment of the Late Middle Japanese onbin/vowel-coalescence change /au/ > /ɔː/ (later /oː/) and the development of the classical 助動詞 む into the modern hortative -u. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

5. 国立国語研究所 (NINJAL). 『現代日本語書き言葉均衡コーパス』(BCCWJ). https://clrd.ninjal.ac.jp/bccwj/ (corpus used to confirm naturalness/frequency of cited example patterns). ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹

6. The Volitional: ～よう. Japanistry. https://www.japanistry.com/the-volitional/. Godan "shift the final kana to the o-row and add う" rule, plus the volitional + と思う resolution sense and volitional + かな pondering. (limitation) ↩ ↩² ↩³ ↩⁴

7. Japanese Verb Volitional Form よう. Tofugu. https://www.tofugu.com/japanese-grammar/verb-volitional-form-you/. The self-resolve / talking-to-oneself use and the casual-register framing relative to ～ましょう. (limitation) ↩ ↩²

8. Makino, Seiichi, and Michio Tsutsui. A Dictionary of Basic Japanese Grammar. The Japan Times, 1986. Entry "(y)ō to omou ＜ようと思う＞": volitional + と思う expresses the first-person speaker's intention; for a third party's intention と思っている is used. ↩ ↩²

9. 〜ようと思う・〜おうと思う, JLPT N4. Bunpro grammar reference. https://bunpro.jp/grammar_points/%E3%82%88%E3%81%86%E3%81%A8%E6%80%9D%E3%81%86-%E3%81%8A%E3%81%86%E3%81%A8%E6%80%9D%E3%81%86. Volitional + と思う frames a plan as a thought (softer, less binding than つもりだ); と思う is for the speaker's own intention, と思っている for a third party's. ↩ ↩² ↩³ ↩⁴ ↩⁵