I thought I read somewhere that Latin verbs usually have about 150 different endings, but when I looked over a paradigm table I only found around 90. How many distinct forms do you need to memorize, say, for a regular verb in -are, to know all the inflections of the verb?
Here is a count of different verb forms for a verb like amare. Including or excluding some forms is a matter of taste, like passive imperatives which only seem common for deponent verbs. Perhaps some might also want to include comparatives or superlatives of participles. The point is that there are different legitimate ways to count, and this is only one. Declination of participles could also be considered to be outside the realm of verb forms; with little exceptions participles are just adjectives. I will give detailed calculations so that anyone can easily pick which forms they wish to include and end up with their own number.
- Active personal forms with 6 persons (60 total):
- indicative (6 tenses)
- conjunctive/subjunctive (4 tenses)
- Passive personal forms with 6 persons (half of the tenses use a participle and esse) (30 total):
- indicative (3 tenses)
- conjunctive/subjunctive (2 tenses)
- Personal forms with less than six persons (6 total):
- present active imperative (2 persons)
- future active imperative (4 persons)
- present and future passive imperatives not used for non-deponent verbs? See the separate question.
- Infinitives (only those that are formed without esse or ire) (3 total):
- present active and passive
- perfect active
- Supine (2 cases)
- Gerund (4 cases)
- Participles and gerundive (144):
- gerundive (3 genders, 2 numbers, 6 cases)
- present active participle (3 genders, 2 numbers, 6 cases)
- future active participle (3 genders, 2 numbers, 6 cases)
- perfect passive participle (3 genders, 2 numbers, 6 cases)
Apart from the full declension of participles and gerundive, I think one has to know all these forms to be able to reproduce any given form. Note that I have not listed forms like amatus sis, since they are composed from esse and a form of amare already on the list.