Spanish Irregular Future Tense Stems

In the Spanish future tense (Futuro Simple), the endings (-é, -ás, -á, -emos, -éis, -án) are added directly to the infinitive for regular verbs. However, twelve common verbs use irregular stems instead. These stems either drop an 'e' (e.g., poder -> podr-, saber -> sabr-, haber -> habr-), replace a vowel with a 'd' (e.g., tener -> tendr-, salir -> saldr-, venir -> vendr-), or are completely shortened (e.g., hacer -> har-, decir -> dir-). Once the stem is changed, the endings are completely regular.