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sum: I am, I was, I shall be

The verb "to be" in the present, imperfect and future.

LatinIntermediate Latin · Verbs: the present systemAbout 3 min: 1 reading, 2 practiceUpdated

After this lesson you can
  • Give all three tenses of sum
  • Use the six personal endings to find who is meant
  • Translate est, erat and erit correctly
Latin Level 2: verbs and the other declensions: lesson 1 of 35
  1. Intermediate Latin · Verbs: the present system
  2. sum: I am, I was, I shall be 3 min
  3. The present of amō and moneō 4 min
  4. The imperfect: was doing 4 min
  5. The future: will do 3 min
  6. The dative with adjectives 3 min
  7. The present of regō and audiō 4 min
  8. The imperfect of regō and audiō, and verbs that take the dative 3 min
  9. The future of regō and audiō 3 min
  10. capiō, and giving orders 3 min
  11. Intermediate Latin · The passive voice
  12. The passive: being done to 3 min
  13. The passive of regō, audiō and capiō; passive infinitives 3 min
  14. Synopses, and the ablative of "from" 3 min
  15. Intermediate Latin · The perfect tenses
  16. fuī, fueram, fuerō: the perfect tenses of sum 3 min
  17. The perfect active: did, have done 5 min
  18. Had done, will have done: pluperfect and future perfect active 3 min
  19. amātus sum: the perfect passive 4 min
  20. Principal parts, prepositions, and yes-or-no questions 5 min
  21. possum, "I can", and the infinitive 3 min
  22. Intermediate Latin · Pronouns
  23. quī, quae, quod: who, which, that 4 min
  24. Intermediate Latin · The third declension
  25. rēx, rēgis: the third declension 4 min
  26. hostis, urbs, mare: i-stems 4 min
  27. vīs and iter; gender in the third declension 4 min
  28. omnis, ācer, pār: third-declension adjectives 3 min
  29. Intermediate Latin · The fourth and fifth declensions
  30. manus, cornū: the fourth declension 3 min
  31. Rōmae, domī, Athēnīs: place and the locative 4 min
  32. diēs, rēs: the fifth declension and the ablative of time 3 min
  33. Intermediate Latin · Pronouns
  34. ego, tū, sē: personal and reflexive pronouns 4 min
  35. ipse, "himself", and īdem, "the same" 3 min
  36. hic, iste, ille: this and that 4 min
  37. aliquis, quīdam, quisque: someone, a certain, each 3 min
  38. Intermediate Latin · Comparison
  39. clārior, clārissimus: comparing adjectives 4 min
  40. melior, optimus: irregular comparison, plūs, and "by how much" 3 min
  41. clārē, fortiter: adverbs and their comparison 4 min
  42. Intermediate Latin · Numerals
  43. ūnus, duo, trēs: numerals, "of" the whole, and "for how long" 5 min
  44. Intermediate Latin · Deponent verbs
  45. hortor, sequor: deponent verbs 3 min

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Pairs with D'Ooge, Latin for Beginners (Ginn, 1909), Lesson XVIII ("The Present, Imperfect, and Future Tenses of sum"), §§ 119–123

What it is

A Latin verb shows who does something with its ending, so it needs no "I", "you" or "they". The six active endings are:

SingularPlural
1st person-m or -ō (I)-mus (we)
2nd person-s (you)-tis (you, more than one)
3rd person-t (he, she, it)-nt (they)

Sum (I am) is irregular, but its endings follow this pattern:

PresentImperfectFuture
Isumeramerō
youeserāseris
he, she, itesteraterit
wesumuserāmuserimus
you (pl.)estiserātiseritis
theysunteranterunt

Quick check

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  1. What does erant mean?

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    they were. The imperfect of sum: eram, erās, erat … erant.

Why it matters

Sum is one of the most common verbs in Latin. The pattern of its future, erō, eris, erit (endings -ō, -is, -it), comes back in the future of the first two conjugations (amābō, amābis, amābit) and in the present of the third (regō, regis, regit). Learning it well now pays off in every later verb lesson.

Worked example

  • Hodiē in lūdō sumus. → Today we are in school.
  • Nūper Sextus īrātus erat. → Recently Sextus was angry.
  • Mox laetī eritis. → Soon you (plural) will be happy.

Common mistake

Mixing up eris (you will be) and erās (you were). The future has -i- (eris, erit, erimus, eritis); the imperfect has -a- (erās, erat, erāmus, erātis).

Key terms

sum, esse
to be
personal ending
the ending that shows the person: -ō/-m, -s, -t, -mus, -tis, -nt
hodiē
today
mox
soon
nūper
recently

Practise the key terms

Tap a card to turn it over. 5 cards.

FrontBack
sum, esseto be
personal endingthe ending that shows the person: -ō/-m, -s, -t, -mus, -tis, -nt
hodiētoday
moxsoon
nūperrecently

Practice

Recognition drill

Pick the right answer, as fast as you can.

All pairs

Tap a card to turn it over. 6 cards.

FrontBack
sumuswe are
estisyou (pl.) are
erathe / she / it was
erāmuswe were
erōI shall be
eruntthey will be

Quick quiz

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  1. "You (one person) will be"

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    eris. Future of sum: erō, eris, erit.

  2. Which ending means "we"?

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    -mus. First person plural: -mus.

Practise speaking

Studyfern has no voice tools of its own. To practise out loud, copy this prompt into a voice-capable AI assistant and talk with it.

You are a patient Latin tutor. Use the classical pronunciation only, never the Church one: c is always k, g is always hard, v sounds like w, ae like the ai in aisle, and long vowels are held longer. Speak slowly. Use only these Latin words: sum, es, est, sumus, estis, sunt, eram, erō, hodiē, mox, nūper. Give me a person and a tense in English (for example 'we were', 'they will be', 'you are'), and I will say the Latin form of sum. Do 10 forms. After each answer, tell me what kind of mistake I made, if any, and let me try again, then tell me one thing to improve. Keep every reply under 2 sentences. If I need a name or a town, I will make one up. Speak English except for the Latin itself.

Listen too. Listen to native speakers before and after: see the free listening and shadowing links.

Good to know. AI feedback on pronunciation is hit and miss, so check yourself against native recordings. This course teaches the classical pronunciation (see lesson 1); AI voices may mix it with the Church (Italian-style) one, so ask for classical and check against lesson 1. Don't share personal details: use a made-up name and town.

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In short

  • Endings show the person: -ō/-m, -s, -t, -mus, -tis, -nt.
  • Present: sum, es, est, sumus, estis, sunt.
  • Imperfect: eram, erās, erat, erāmus, erātis, erant.
  • Future: erō, eris, erit, erimus, eritis, erunt.

Mastery check

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Check yourself

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  1. Translate erimus.

    Show answer

    We shall be.

  2. Give "you (plural) were".

    Show answer

    erātis.

  3. What does the ending -nt tell you?

    Show answer

    The subject is "they" (third person plural).

Further reading

  • D'Ooge, Latin for Beginners, Lesson XVIII, §§ 119–123. Public domain; Project Gutenberg.