Japanese Verb Conjugator

Japanese verbs are classified into three groups. Godan verbs (Group 1, also called u-verbs) end in a consonant plus u (such as nomu, kaku, hanasu) and their stem vowel changes depending on the conjugation. Ichidan verbs (Group 2, also called ru-verbs) end in iru or eru (such as taberu, miru, neru) and conjugate by simply dropping the final ru and adding the appropriate ending. The third group consists of two irregular verbs: suru (to do) and kuru (to come), which follow unique conjugation patterns that must be memorized individually.

The te-form is one of the most important conjugation forms in Japanese. For ichidan verbs, drop the final ru and add te (taberu becomes tabete). For godan verbs, the te-form depends on the final kana of the dictionary form: verbs ending in u, tsu, or ru change to tte; verbs ending in mu, bu, or nu change to nde; verbs ending in ku change to ite (except iku which becomes itte); verbs ending in gu change to ide; and verbs ending in su change to shite. The irregular verbs suru becomes shite and kuru becomes kite.

The masu form is the polite present/future tense form of Japanese verbs. It is used in formal and everyday polite conversation, making it one of the first verb forms learners encounter. To form it, ichidan verbs drop the final ru and add masu (taberu becomes tabemasu). Godan verbs change the final u-sound to the corresponding i-sound and add masu (nomu becomes nomimasu, kaku becomes kakimasu). The irregular verbs suru becomes shimasu and kuru becomes kimasu.

The potential form expresses ability, meaning "can do" or "is able to do" something. For example, taberareru means "can eat." The passive form expresses that the subject is affected by an action performed by someone else, as in taberareru meaning "is eaten." While ichidan verbs share the same potential and passive form (both end in rareru), godan verbs have distinct forms: the potential changes the final u-sound to eru (nomu becomes nomeru), while the passive changes it to areru (nomu becomes nomareru).

For JLPT N5, you need to master the masu form, nai form (negative), ta form (past), and te-form. These cover polite speech and basic sentence construction. JLPT N4 adds the potential form, volitional form, and conditional forms. JLPT N3 requires understanding of the passive and causative forms. For JLPT N2 and N1, you need to know the causative-passive form and be comfortable using all conjugations fluently in complex grammar patterns. Mastering the te-form is especially critical as it is the foundation for many advanced grammar structures.