Counting in Irish: From a haon to a deich and Beyond

Numbers are one of the first things to learn in any language. Irish has a clear system, with one wrinkle: the form you use when counting on its own differs from the form used before a noun.

Counting (1 to 10)

When you just recite numbers, they start with a:

Number	Irish
1	a haon
2	a dó
3	a trí
4	a ceathair
5	a cúig
6	a sé
7	a seacht
8	a hocht
9	a naoi
10	a deich

Note the h in a haon and a hocht: it's added because the word a is followed by a vowel.

11 to 20

Add déag ("ten") to 1–9:

• 11 — a haon déag
• 12 — a dó dhéag
• 13 — a trí déag
• 14 — a ceathair déag
• 15 — a cúig déag
• 20 — fiche

Larger numbers

• 30 — tríocha
• 100 — céad
• 1,000 — míle

Numbers before nouns

When you say "two cats", the number comes before the noun and takes a slightly different form:

• aon — one (as in aon chat amháin, one cat)
• dhá — two (as in dhá chat, two cats)

Notice that these numbers cause a lenition on the noun (cat becomes chat). That is why mutations matter so much in Irish.

Useful phrases

• Cé mhéad? — How many? / How much?
• Tá dhá pháiste agam. — I have two children.
• Tá mé fiche bliain d'aois. — I am twenty years old.

Common mistakes

1. Using the counting form (a dó) before a noun.
2. Forgetting the mutation after certain numbers.
3. Dropping the fada in cúig or trí.

Tips

1. Learn 1–10 first, then add déag.
2. Count real objects aloud.
3. Use the dictionary to check number forms and mutations.

Look up any word with English Irish Dictionary →