Future Indicative of Third and Fourth Conjugations

Third-, third-iō-, and fourth-conjugation verbs do not use the b-future. Their future indicative has -a- in the first-person singular and -ē- in the other persons: regam, regēs, reget “I will rule, you will rule, he or she will rule.” Third-iō and fourth-conjugation verbs retain an i before those future vowels: capiam, capiēs and audiam, audiēs.

These are present-system forms. Build them from the present pattern supplied by the first two principal parts, not from the perfect stem and not from an English translation. The regular forms are neutral Classical prose; where a shape has another possible parse, syntax and context decide between them.

First- and second-conjugation verbs use a different formation, surveyed in Future Indicative of First and Second Conjugations. The contrast is worth learning as two systems rather than one list with many exceptions.

Three patterns, one future system

The third-conjugation sequence is -am, -ēs, -et, -ēmus, -ētis, -ent. Add i before that sequence for third-iō and fourth-conjugation verbs. The resulting first-person forms end in -iam; the plural third-person forms end in -ient.

The final personal ending still identifies the subject. Capiētis is second-person plural, whereas capient is third-person plural. English represents both with separate pronouns plus “will”; Latin packages future, person, and number into one word.

Meaning: future time, indicative presentation

The future indicative presents an event as expected within the speaker’s view of reality. It can make a prediction, state a plan, promise, warn, or describe the consequence of a condition. Those shades come from context. Morphologically, the form remains future indicative.

The conditional example uses future indicative ēligēs and inveniēs for an open, prospective relationship. English normally has present “if you choose” in the if-clause, but Latin can mark both actions as future. This does not mean Latin mechanically uses a future wherever English has will. Latin present forms can also refer to a scheduled or imminent future, and other moods express imagined or less factual conditions.

Likewise, a future statement may function pragmatically as an instruction: hoc faciēs can mean “you will do this.” It is still indicative in form, often with a firm or authoritative tone (formal). The straightforward command hoc fac is imperative. Do not confuse communicative force with morphological mood.

A crucial ambiguity: first singular and present subjunctive

For third-conjugation verbs, regam can be either first-person singular future indicative (“I will rule”) or first-person singular present subjunctive (“I may rule / let me rule”), because the forms are identical. Capiam and audiam have the same ambiguity. Context, not the word in isolation, determines the parse.

In the first sentence, crās and the independent assertion support future indicative. In the second, ut after rogat introduces a subordinate clause requiring the subjunctive. A parser should therefore record both morphological possibilities and then use clause structure to choose.

The other persons contrast more clearly. Future regēs differs from present subjunctive regās; future reget differs from subjunctive regat. Macrons make the second-person distinction visible in pedagogical spelling, but authentic Latin manuscripts and many editions omit them. Syntax remains indispensable.

The passive future

Passive endings attach to the same future bases:

The alternative second-person singular in -re is also Classical: regēre, capiēre, audiēre. These passive forms are neutral Classical prose, not special poetic inventions.

Notice that aedificābuntur is first conjugation and uses b, while third-conjugation dūcentur uses the a/e-future. A sentence may freely combine the two future systems. The conjugation of each Latin verb—not the shared English word “will”—selects its form.

Distinguishing present and future

Third- and fourth-conjugation futures can resemble presents, especially when vowel length is not printed:

Macrons are a teaching aid, not a feature of most ancient writing. When they are absent, reges can even coincide in spelling with accusative plural rēgēs “kings.” Sentence syntax supplies the category: a noun cannot serve as the finite predicate required by its clause, and a verb will have arguments appropriate to regō.

Common Mistakes

1. Adding the b-future to every conjugation. Third and fourth conjugations use the a/e-future.

2. Losing the i in third-iō and fourth-conjugation forms. Keep it before the future vowel.

3. Using the future indicative where syntax requires a present subjunctive. A request with ut selects the subjunctive.

4. Building the future from the English translation or perfect stem. Retrieve the present conjugation first.

5. Confusing active and passive. The final ending decides who acts and who undergoes the action.

Key Takeaways

Third-conjugation futures use -am, -ēs, -et, -ēmus, -ētis, -ent. Third-iō and fourth-conjugation futures insert i: capiam, capiēs; audiam, audiēs. The first-person singular is formally identical to the present subjunctive, so syntax and context must complete the analysis. Build from Latin principal parts, preserve the active-passive distinction, and never let English “will” choose a Latin conjugation for you.