Latin Vowel Quantity (macrons/macra)

Distinguishing Vowels
Typing Macrons on the Computer
General Rules
Rules by Part of Speech: Verbs
Rules by Part of Speech: Nouns/Adjectives
Rules by Vowel


Macrons (long vowel marks) are a guide for pronunciation, indicating the difference between long and short vowels. Different languages express this difference in different ways. English sometimes uses a final “magic e:” man vs. mane; kit vs. kite, e.g. Greek has different letters for long e (η “eta”) vs. short e (ε “epsilon”) and long o (ω “omega”) and short o (ο “omicron”). Including the macrons is also like including the accidentals (sharps and flats) in music or using training wheels on a bicycle.


Accent in Latin is determined by the quantity of the next to last syllable. Vowel length affects this.

Distinguishing Vowels

Some words or forms of words in Latin are differentiated only by vowel length: os (“bone”) vs. ōs (“mouth”), puella (nominative case) vs. puellā (ablative case).


Classical Latin poetry is based on patterns of syllable quantity (not rhyme schemes or patterns of stress accents). Vowel quantity is a part of this.

Typing macrons on the computer

To enter macrons on the computer (MS word): In the Insert Menu, select Symbol; scroll down in most any of the fonts (e.g. Tahoma; normal) until you see the appropriate letter with the long vowel mark. Click on “insert.” If you will be doing a lot and want to set up a macro; CTRL+SHIFT+(vowel) is a good short-cut key (e.g. ctrl+shift+a for ā). To change to a capital, SHIFT+F3. (CTRL+space bar always gets you back to the default font if you get stuck in a different font).

General Rules

I. Final -ī, final -ō, and final -ū are regularly long (always for words of more than two syllables).
A. final long -ī:
amīcī (2nd decl. gen. s.; nom. pl)
sorōrī (3rd decl. dat. s.)
omnī (3rd decl. -i stem abl. s.)
audī (imperative)
fēcī (1st. s. perfect)
amāvistī (2nd s. perfect)
B. final long -ō
vocō: 1st person singular verbs ending
lēgātō: 2nd decl. dat./abl. singular
homō, multitūdō: 3rd. decl. nom. sing. long -ū
manū: 4th decl. abl. sing.
II. a long vowel shortens before:
A. final -r, -m, -t
dūcō (present active) but dūcor (present passive)
amor (nom. s.) but amōris, etc. (3rd decl. masc./fem. nouns in -or)

amabam (imperfect) amāmus
amās amātis
amat (3rd plural. see B next)
B. before -nt(-) anywhere in a word
amant (amā-)
amantur (passive)
c. before another vowel
timeō (timē-)
audiēs (audī-)
N.B. The vowel stem on 1st (-ā-), 2nd (-ē-) and 4th (-ī-) conjugation verbs is long except where it shortens by these rules.
III. Note these pairs
verb: dūcō (long “ū”) vs. nouns: dux, ducis (short)
verb regō (short “e”) vs. noun: rēx, rēgis (long)
IV. Note:
Nominative plural: -ī, -ēs, (-ūs, -ēs)
*except neuter short -a
Genitive plural: long -ārum, -ōrum, (-ērum)
Accusative Plural -ās, -ōs, – ēs, -ūs, -ēs
*except: neuter short -a
Ablative singular: long -ā, -ō, (3rd declension -i stem) -ī, (-ū, -ē)
*except: 3rd declension consonant stem short -e
Dative/Ablative plural:
-īs (long)
-ibus (short)
Verbs: 2nd person plural active: short -tis

By Part of Speech: Verbs

1. The vowel before the imperfect -bā- suffix is always long. The “a” in the “bā” suffix is long except where it shortens (II above).
2. the vowel before a “v” perfect is long.
3.“a” and “e” as a regular vowel before a personal verb ending are usually long;
“i” before a personal verb ending is more often short (because usually added by Linguistic Rules #12)
except for 4th conjugation verbs (which are long (-ī” stem).
1st conjugation:
vocēs (present subjunctive)
vocārēs (imperfect subjunctive)
2nd conjugation:
habeās (subjunctive)(“e” shortens: II above)
3rd conjugation
regēs (future)
regās (subjunctive)
regis (present indicative)
imperfect of sum: erās
imperfect: vocābās
pluperfect active: vocāverās

future of sum: eris
future: vocābis
future perfect vocāveris
N.B. this does not apply to exceptional forms or the stem vowel of “sum”:
3rd conjugations 1st sing. future active:
dūcam (short “a;” “-ē” in other forms)
3rd conjugation 2nd sing. present passive indicative
dūceris (short”e;” “i” in other forms) (See Linguistic Rules #11)
“sum:” esse, es, est, estis, eram, erō, etc. (all with short “e”)

By Part of Speech: Nouns/Adjectives

Dative singular (not a diphthong): long
(final -o) -ō
(final -i) -ī, -uī, -eī
Ablative Singular: long -ā, -ō, (3rd declension -i stem) -ī, -ū, – ē
*except: 3rd declension consonant stem -e
Nominative Plural: -ī, -ēs, -ūs, -ēs
*except: neuter -a
Genitive Plural: 2 syllable ending: long -ārum, -ōrum, -ērum
Dative/Ablative plural:
-īs (long)
-ibus (short)
Accusative plural: -ās, -ōs, -ēs, -ūs, -ēs
*except: neuter -a

By Vowel

(cf. Verbs 3 above)
Ablative: puellā Nominative singular: 1st declension: puella
genitive plural 1st decl: puellārum plural (neuter)
2nd: bella
3rd: nomina
acc. pl. 1st decl.: puellās
present (imperfective) stem:
1st conjugation verbs: vocā
imperfect: -bā-
present (imperfective) stem:
2nd conjugation verbs: vidē
3rd decl. abl. sing. frātre
future of 3rd/4th conj. verbs:
capēris (vs. present caperis)(See Verbs 3 note)
3rd (-iō) conj. sing. imperative: cape
3rd plural perfect ending: -ērunt 3rd plural pluperfect ending: -erant
perfeect stem of some verbs:
adverbs formed from 1st/2nd decl. adjectives: miserē
5th decl. abl. sing.: rē
noun stem “rēg-” king vs. verb “reg-” rule
NOTE: Final -ī is long
1st person sing. perfect ending: audīvī 3rd decl. gen. sing.: urbis
2nd person sing. perfect ending: audīvistī
2nd person plural passive ending: mittiminī
present (imperfective) stem
4th conjugation verbs: audī-
2nd decl. gen. sing/nom. pl.: amīcī
3rd decl. dat. sing./i-stem abl. sing.: marī
1st/2nd decl. dat/abl. pl.:
vīs, vīr- force (vs. vir, virī man)
NOTE: final -o is usually long
3rd decl. m/f. stem: sorōr- 3rd decl. nt. stems: corpor-
2nd decl. gen. pl.: lēgātōrum
2nd decl. acc. pl.: lēgātōs
NOTE: Final -u is regularly long for words of more than two syllables
4th abl. sing.: manū
4th decl. gen. s.; nom/acc pl.: manūs
verb stem “dūc-” lead vs. noun stem “duc-“