The perfect system uses the perfect stem, which is found from the 3rd principle part.

This stem has no thematic vowel, so in my opinion the perfect system is a lot easier to deal with than the present system.

Perfect active verbs are different in form to perfect passive verbs. Perfect active verbs change their ending in various ways. Perfect passive verbs use the perfect passive participle, and then add a form of sum.

The PPP agrees with the subject in gender and number, but is always nominative case.

This page is structured as πŸŸ₯voice > 🟨tense > 🟦mood

finding the perfect stem

from principal part

non-deponent: take off the Δ«.
fundo, fundere, fudi, fusum β†’ fud
cogito, cogitare, cogitavi, cogitatum β†’ cogitav

deponent: they have no perfect stem. They never use it anyways, since they don't have perfect active forms. To find the PAP, take off the "sum" and remember to decline it.

πŸŸ₯ active

Active verbs in the perfect system all follow the pattern perfect stem + personal ending, where the endings are unique for each tense-mood combination. Most can be thought of as infix + [-m -s -t -mus -tis -nt] or a form of sum/esse.

🟨 perfect

🟦 indicative

the personal endings are [-i -isti -it -imus -istis -erunt]

1st conjugation - tempto, temptare, temptavi, temptatum
temptavi, temptavisti, temptavit, temptavimus, temptavistis, temptaverunt

2nd conjugation - sedeo, sedere, sedi, sessum
sedi, sedisti, sedit, sedimus, seditis, sederunt

3rd conjugation - tango, tangere, tetigi, tactum
tetigi, tetigisti, tetigit, tetigimus, tetigistis, tetigerunt

3rd -io conjugation - pario, parere, peperci, partum
peperci, pepercisti, pepercit, pepercimus, pepercistis, pepercerunt

4th conjugation - punio, punire, punivi, punitum
punivi, punivisti, punivit, punivimus, punivistis, puniverunt

I use isti as an 'indicator' for the perfect tense. Not that reliable though, because verbs like existo, existere. Its 2nd person present is existis.

🟦 subjunctive

with infix: perfect stem + eri + [-m -s -t -mus -tis -nt]

e.g. capio, capere, cepi, ceptum
cep + eri + m

with forms of sum: similar to the future active indicative, but erim eris erit erimus eritis erint, so erim instead of ero and erint instead of erunt.

ceperim
ceperis
ceperit
ceperimus
ceperitis
ceperint

these are the exact same as the future perfect indicative except -erim is -ero in the future perfect indicative

🟨 pluperfect

🟦 indicative

the endings are [-eram -eras -erat -eramus -eratis -erant].

These are exactly the same as the imperfect active indicative forms of sum/esse.

🟦 subjunctive

with infix
perfect stem + isse + [-m -s -t -mus -tis -nt]

as forms of sum
imperfect active subjunctive forms (essem, esses, esset, essemus, essetis, essent) but the leading e changes to an i.

OR you can have it as the perfect active infinitive + [-m -s -t -mus -tis -nt]

🟨 future-perfect

the subjunctive doesn't exist

🟦 indicative

the endings are [-ero -eris -erit -erimus -eritis -erint].

These are the same as the future active indicative forms of sum/esse, EXCEPT for erint - the form of sum is erunt.

πŸŸ₯ passive

Perfect passive verbs use the perfect passive participle, and then add a form of sum.

NOTA BENE: the PPP agrees with the subject in gender and number, but is always nominative case.

🟨 perfect

🟦 indicative

PPP + present active indicative forms of sum
PPP + [sum es est sumus estis sunt]

🟦 subjunctive

PPP + present active subjunctive forms of sum
PPP + [sim sis sit simus sitis sint]

🟨 pluperfect

🟦 indicative

PPP + imperfect active indicative forms of sum
PPP + [ eram eras erat eramus eratis erant ]

🟦 subjunctive

PPP + imperfect active subjunctive forms of sum
PPP + [essem esses esset essemus essetis essent]

arcesso, arcessere, arcessivi, arcessitum to send for, fetch
arcessitus (-a -um) essem
arcessitus (-a -um) esses
arcessitus (-a -um) esset
arcessitus (-a -um) essemus
arcessitus (-a -um) essetis
arcessitus (-a -um) essent

🟨 future-perfect

🟦 indicative

ugh just figure it out yourself

it's just PPP + future active indicative sum

subjunctive future perfect doesn't exist, as usual