Futurum is a past tense. Its formation is simple: we take the 3rd person plural present and change -ant into -abo, -ent into -ebo, -unt into -am. The endings of this tense when 1st person ends in -bo are like in praesens in the 3rd conjugation (-bo, -bis, -bit, -bimus, -bitis, -bunt). When the 1st person ends in -am, before other endings -a- changes into -e- : these verbs behave like prasens of the 2nd conjugation except the 1st person sg. (-am, -es, -et, -emus, -etis, -ent). Examples : I conjugation: voco, vocare, vocant:

person	singular	plural
1	vocabo	vocabimus
2	vocabis	vocabitis
3	vocabit	vocabunt

II conjugation: video, videre, vident:

person	singular	plural
1	videbo	videbimus
2	videbis	videbitis
3	videbit	videbunt

In the IV conjugation the 3rd person plur. ends in -iunt :

person	singular	plural
1	veniam	veniemus
2	venies	venietis
3	veniet	venient

III conjugation, regular verbs:

person	singular	plural
1	mittam	mittemus
2	mittes	mittetis
3	mittet	mittent

III conjugation, verbs adding -i-:

person	singular	plural
1	faciam	faciemus
2	facies	facietis
3	faciet	facient

The verbs which form imperfectum irregularly, do the same in futurum. The verb sum forms futurum irregularly : sum > ero (other persons like vocabo)

person	singular	plural
1	ero	erimus
2	eris	eritis
3	erit	erunt

Similarly : possum, potest > potero, prosum, prodest > prodero, absum, abest > abero. Other irregular verbs : ire and its forms with prefixes have -ibo : ire > ibo, abire > abibo The other verbs form futurum regularly : fero, ferre, ferunt > feram, feres, feret, feremus, feretis, ferent volo, velle, volunt > volam, voles... nolo, nolle, nolunt > nolam, noles... malo, malle, malunt > malam, males... fio, fieri, fiunt > fiam, fies... inquam has only forms inquies and inquies. Futurum passivi has regular passive endings : when there is -b- (I, II conj.): -bor, -beris, -bitur, -bimur, -bimini, -buntur (like III conj.) when there is -am (III, IV conj.): -ar, -eris, -etur, -emur, -emini, -entur (like II conj. except -ar) I, II conj. (futurum in -bo > -bor)

person	singular	plural
1	vocabor	vocabimur
2	vocaberis	vocabimini
3	vocabitur	vocabuntur

When there is -am:

person	singular	plural
1	mittar	mittemur
2	mitteris	mittemini
3	mittetur	mittentur