Weak verbs

(preterite formed with -aði, -ði, -di, -ti)

Class 1: 1st pers pres sg indic ending in -a; infinitive ending in -a, -ja, -va; any type of stem vowel; preterite formed with -aði, pp with -að.

Class 2: 1st pers pres sg indic ending in -i (no ending when infinitive ends in -á: ná > næ). Infinitive endings in -a (or -ja after g and k) or -á. Preterite formed in the sg with -ði, -di, -ti, pp with -t or -að.

Also belonging to this class are verbs with vowel change in the infinitive and pres indic: segja (sagði, sagt) ég segi, við segjum; and þegja (þagði, þagað) ég þegi, við þegjum. Some verbs of this type have vowel change only in the pres sg indic and not in the infinitive: hafa (hafði, haft) ég hef, and þvo (þvoði, þvegið) ég þvæ, við þvoum. A few verbs with final consonants in the stem take -t to form the pp: haft, horft, keypt (kaupa), sagt.

Class 3: There is no ending in 1st pers pres sg indic and the infinitive ends in -ja; vowel change in the infinitive and in the entire present tense.

Strong verbs

The classes of strong verbs are differentiated by changes in the vowel. Verb endings are the same as in Class 3 of weak verbs with the exception of the 2nd and 3rd pers sg pres indic, where the endings depend on the final letter in the stem; pp ends in -ið.

All strong verbs whose stems end in consonants (other than -n, -r, -s, -x) have the same endings as bíta. Verbs with stems ending in -r, -s, -n and -x or that end in a vowel do not follow this rule and are conjugated as follows:

Seven classes of vowel change

In the following table the 1st pers pres indic is given only where the stem vowel differs from that in the infinitive (i.e. where change occurs).

The vowel changes are given alongside the relevant headword in the dictionary.

Verbs with irregular present tense

These verbs are declined irregularly only in the present tense. Pret indic and subjunctive forms have the same endings as weak verbs, and so only the 1st pers sg indic (or subjunctive where there is no indicative) of the preterite is given. Only vera is irregular in the preterite as well as in the subjunctive of the present tense.