Greek Numbers: Modern Pronunciation, Ancient Numerals & Prefixes Explained

Greek numbers come up in more situations than most people expect. You need them when you’re travelling in Greece, when you’re studying chemistry or biology (mono, di, tri, tetra — those are Greek), when you’re reading about mythology, or when you’ve decided to actually learn the language. And then there’s the separate world of ancient Greek numerals, which look completely different from anything modern.

This guide covers all of it in one place: the modern Greek number system with pronunciation, the classical numeral system from antiquity, the numerical prefixes used in science, and a few cultural curiosities that keep coming up in searches. By the end, you’ll have a complete picture — not just a list of numbers to memorise.

Greek Numbers 1–10: The Foundation

The first ten numbers in Greek are the ones worth memorising properly — everything else builds on them. What I’ve found when learning new languages is that numbers are deceptively tricky: you think you know them, but under pressure (at a till, in a taxi, on the phone) your brain blanks. The way around that is to actually practise them out loud, not just read them off a list.

A few things to know about the Greek alphabet before you start: Greek uses its own script, and several letters look familiar but are pronounced differently. The letter δ (delta) sounds like the “th” in this. The letter γ (gamma) before certain vowels becomes a soft sound similar to “y”. This matters when you read the numbers, because you’ll otherwise mispronounce about half of them.

Here’s the full table for 1–10, with the Greek script, a transliteration, and the pronunciation guide:

Number	Greek	Transliteration	Pronunciation
1	ένα	éna	EH-na
2	δύο	dýo	THEE-oh
3	τρία	tría	TREE-a
4	τέσσερα	téssera	TEH-seh-ra
5	πέντε	pénte	PEN-deh
6	έξι	éxi	EHK-see
7	επτά	eptá	ep-TAH
8	οκτώ	októ	ok-TOH
9	εννέα	ennéa	eh-NEH-a
10	δέκα	déka	THEH-ka

One thing that trips people up early: “two” in Greek is δύο, and that leading δ sounds like “th” — so it’s “THEE-oh”, not “DEE-oh”. I’ve heard this mispronounced constantly, including by people who had studied Greek for months. The phonetics just don’t match English intuition.

Why Greek Numbers Have Gender

Modern Greek numbers 1–4 change form depending on the gender of the noun they describe. So “one” isn’t always ένα — it can be ένας (masculine) or μία (feminine). The same applies to 3 and 4. From 5 upwards, the numbers are invariable — they don’t change with gender, which makes them easier.

For basic counting, shopping, telling time, and ordering food, you’ll mostly use the neuter form (ένα, δύο, τρία…), and nobody will correct you if you get the gender wrong. But if you’re serious about the language, this is worth knowing early.

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Greek Numbers 1–20

Numbers 11–19 in Greek follow a fairly consistent compound pattern: they’re formed from the base number plus the word for ten (δέκα). This is similar to how English “fourteen” is “four + ten”, except in Greek the order is flipped: ten comes first.

Eleven is έντεκα (énteka) and twelve is δώδεκα (dódeka) — these two are irregular and need to be learnt separately. From 13 onwards, the pattern kicks in properly: δεκατρία (13), δεκατέσσερα (14), and so on.

Number	Greek	Pronunciation
11	έντεκα	EN-deh-ka
12	δώδεκα	THOH-deh-ka
13	δεκατρία	theh-ka-TREE-a
14	δεκατέσσερα	theh-ka-TEH-seh-ra
15	δεκαπέντε	theh-ka-PEN-deh
16	δεκαέξι	theh-ka-EHK-see
17	δεκαεπτά	theh-ka-ep-TAH
18	δεκαοκτώ	theh-ka-ok-TOH
19	δεκαεννέα	theh-ka-eh-NEH-a
20	είκοσι	EE-koh-see

Twenty — είκοσι — is another one to learn separately. It doesn’t follow the pattern of the teens, and it’s used very frequently (prices, ages, quantities). Get it solid before moving on.

Greek Numbers 1–100: The Full System

Once you have 1–20 down, the rest of the system becomes manageable. Greek builds compound numbers the same way English does: twenty-one is είκοσι ένα (literally “twenty one”), thirty-five is τριάντα πέντε, and so on. The tens just need to be memorised — there’s no completely predictable pattern linking them to the base numbers.

The Tens

Number	Greek	Pronunciation
20	είκοσι	EE-koh-see
30	τριάντα	tree-AN-da
40	σαράντα	sa-RAN-da
50	πενήντα	peh-NIN-da
60	εξήντα	ehk-SIN-da
70	εβδομήντα	ev-thoh-MIN-da
80	ογδόντα	og-THON-da
90	ενενήντα	eh-neh-NIN-da
100	εκατό	eh-ka-TOH

How to Form Numbers in Between

Combining a ten with a unit is simple: just place them next to each other with a space. 21 = είκοσι ένα, 45 = σαράντα πέντε, 78 = εβδομήντα οκτώ. No connecting word is needed, unlike in some other European languages.

A practical note on hundreds: 100 is εκατό, but 200 is διακόσια, 300 is τριακόσια, and so on — these aren’t just “two hundred” compounds, they have their own forms. For everyday use up to 100, what’s above is everything you need.

If you want to practise these numbers in context — how they sound in real sentences, how Greeks actually count — the Greek language resources on this site are a good next step.

Ancient Greek Numbers: The Classical Numeral System

This is where many people get confused — and understandably so. When people search for “Greek numerals”, they sometimes mean the modern spoken numbers above, but just as often they mean the ancient system of symbols used in classical antiquity. These are two completely different things.

Ancient Greek used not one but two main numeral systems over the course of its history: the Attic (or Acrophonic) system and the Milesian (or Alphabetic) system. The Milesian system became standard and is the one you’ll most often encounter in classical texts.

The Attic / Acrophonic System

The Attic system was used in Athens and is the older of the two. It works similarly to Roman numerals — each value has a dedicated symbol, and you combine them. The symbols were derived from the first letter of the Greek word for each number:

Value	Symbol	Greek word (origin)
1	Ι	Single stroke
5	Π	Πέντε (pénte)
10	Δ	Δέκα (déka)
100	Η	Ἑκατόν (hekaton)
1,000	Χ	Χίλιοι (chilioi)
10,000	Μ	Μύριοι (myrioi)

You can see where the word myriad comes from — directly from the Greek symbol for 10,000.

The Milesian / Alphabetic System

The Milesian system assigned numerical values to all 24 letters of the Greek alphabet, plus three archaic letters that had otherwise fallen out of use. This is the system used in classical manuscripts and still seen today in certain liturgical and scholarly contexts.

Value	Letter	Name
1	α	Alpha
2	β	Beta
3	γ	Gamma
4	δ	Delta
5	ε	Epsilon
6	ϛ	Stigma (archaic)
10	ι	Iota
20	κ	Kappa
100	ρ	Rho
1,000	α with left stroke	Alpha (with diacritic)

To indicate that a letter is being used as a numeral rather than a letter, ancient writers placed a horizontal stroke above it (called keraia). Without that marker, the context had to make it clear — which is one reason ancient texts require careful reading.

For a deeper look at how the Greek alphabet underpins the numeral system, the overview at Encyclopaedia Britannica is a reliable starting point.

Greek Numerical Prefixes: mono, di, tri, tetra and Beyond

This section is the one most language guides leave out — and it’s arguably the most useful for anyone working in science, medicine, or just trying to understand English vocabulary at a deeper level.

Greek numerical prefixes appear everywhere in modern scientific terminology. When you see “monoxide”, “dioxide”, “trilogy”, “pentagon”, or “octopus”, you’re reading Greek numbers. Understanding these prefixes doesn’t just help with Greek — it helps you decode thousands of English words you already know.

Number	Greek Prefix	English Examples
1	mono-	monoxide, monologue, monarch
2	di-	dioxide, dilemma, dichotomy
3	tri-	triangle, trilogy, tricycle
4	tetra-	tetrahedron, tetrapod, Tetris
5	penta-	pentagon, pentathlon, pentagram
6	hexa-	hexagon, hexameter, hexapod
7	hepta-	heptagon, heptarchy
8	octa- / octo-	octopus, octagon, October*
9	ennea- / nona-	enneagram, nonagon
10	deca-	decade, decathlon, decagram
100	hecto-	hectare, hectolitre
1,000	kilo-	kilogram, kilometre, kilobyte

*October was originally the eighth month in the early Roman calendar — before January and February were added.

In chemistry, these prefixes follow a strict system: carbon monoxide has one oxygen atom, carbon dioxide has two. IUPAC nomenclature (the international standard for chemical naming) uses these Greek prefixes consistently, which is why a student who knows them can decode an unfamiliar compound name without ever having seen it before. It’s a genuine practical skill, not just a curiosity.

Greek Numbers vs. Roman Numerals: What’s the Difference?

This question comes up constantly — and the short answer is: they’re from two different civilisations and have essentially no relationship to each other, despite the fact that both Ancient Rome and Ancient Greece were literate, numerate cultures in the same era.

Roman numerals use Latin letters (I, V, X, L, C, D, M) in a subtractive system: IV means 4 (5 minus 1), IX means 9 (10 minus 1). Greek numerals, as described above, used the Greek alphabet in an additive system — you add up the values of the symbols.

	Roman Numerals	Greek Numerals (Milesian)
Origin	Latin / Roman	Greek alphabet
System	Subtractive (IV = 4)	Additive (each letter = fixed value)
Symbols	I, V, X, L, C, D, M	α, β, γ … (with keraia)
Still used today?	Yes (clocks, chapter numbers, dates)	Rarely (liturgical texts, some academic use)

A common source of confusion: many people who search for “Greek numbers i ii iii iv” are actually looking at Roman numerals and assuming they’re Greek — perhaps because they associate both with classical antiquity. The Romans borrowed many things from the Greeks, but their numeral system wasn’t one of them.

Numbers in Greek Mythology and Culture

Numbers carried symbolic weight in ancient Greek thought in ways that went well beyond counting. The Pythagoreans, followers of the philosopher Pythagoras, believed numbers were the underlying structure of reality — a position that influenced mathematics, music theory, and philosophy for centuries.

Significant Numbers in Greek Mythology

3 — One of the most important numbers in Greek cosmology. The universe was divided into three realms: the sky (Zeus), the sea (Poseidon), and the underworld (Hades). The Fates were three, as were the Graces, the Gorgons, and the Furies. Three was seen as a complete and balanced number.

7 — Considered sacred to Apollo, the god of the sun, music, and prophecy. The Oracle at Delphi was consulted on the seventh day of each month. The Pleiades were seven sisters. The number appeared frequently in ritual contexts.

12 — The twelve Olympian gods defined the Greek pantheon. Twelve also appeared in Heracles’ twelve labours. As a highly composite number (divisible by 1, 2, 3, 4, 6, and 12), it was practically convenient as well as symbolically rich.

10,000 (μύριοι / myrioi) — In ancient Greek, this number meant not just “ten thousand” but essentially “countless” or “innumerable” — the sense it retains in the English word myriad.

The Number 666 in the Greek Context

The number 666 is frequently searched in connection with Greek, largely because the Book of Revelation was originally written in Greek and the famous “number of the beast” appears there as ἑξακόσιοι ἑξήκοντα ἕξ (hexakosioi hexekonta hex — literally “six hundred sixty-six”). Scholars have debated its meaning for centuries; the most widely held modern interpretation is that it was a coded reference to a Roman emperor, using a system called gematria, where letters have numerical values — a practice that draws directly on the Milesian numeral system described above.

How to Learn Greek Numbers Effectively

Numbers are one of those areas where passive recognition isn’t enough. You can read a table like the ones above and feel like you know the material — and then completely blank when a Greek speaker says a price at 60 miles an hour. The gap between recognition and production is real, and it requires active practice to close.

From experience learning several languages — including working through Norwegian from scratch over eight years — the method that actually works for numbers is contextual repetition: using the numbers in real situations rather than drilling abstract lists. Count things around you in Greek. Say your phone number in Greek. Work out prices mentally in Greek before checking.

A structured course helps significantly here, because it builds the necessary audio exposure. The free trial from 17-Minute-Languages’ Greek course is worth trying — it focuses specifically on vocabulary in context, which is where numbers stick best. I’ve found their method works particularly well for exactly this kind of discrete, structured knowledge.

For more conversational practice, Mondly’s Greek programme adds voice recognition and dialogue practice, which helps with number pronunciation specifically — hearing yourself say εβδομήντα and getting feedback is far more useful than reading it.

And if you want to move beyond numbers into practical conversation, the most useful Greek phrases for everyday situations are a natural next step.

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Summary: Greek Numbers at a Glance

Greek numbers exist in three distinct contexts that are often confused with one another:

Modern Greek numbers are the spoken language of contemporary Greece. They use the standard decimal system, have some gender agreement for 1–4, and are pronounced using the modern Greek phonology — which is consistent and learnable, once you accept that δ sounds like “th” and η sounds like “ee”.

Ancient Greek numerals are the written symbols used in classical antiquity — either the Attic acrophonic system (for inscriptions and commerce) or the Milesian alphabetic system (for manuscripts). These are not used in everyday modern Greek.

Greek numerical prefixes (mono-, di-, tri-, tetra-…) are the living legacy of ancient Greek in modern scientific and everyday vocabulary. You use them constantly without thinking about it.

Knowing which question you’re actually asking — and which of these three systems answers it — will save you a lot of confused searching.

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