Free resources ›

Welsh numbers

Welsh has two ways of counting (an old one that counts in twenties and fifteens, and a newer decimal one), and some numbers change with the gender of the noun. This page covers counting to ten (and their short forms), masculine and feminine, the old and new ways, and ordinals (first, second, third).

When a number makes the next word change, the changed word is in bold, with the word it started as in brackets. For the full story of those changes, see Welsh mutations.

Counting to ten

Dim also means "no" or "nothing": dim byd is "nothing at all". Higher up: cant (100), mil (1,000), miliwn (a million).

Short forms: pum, chwe, can, deng…

Six numbers have a shorter form, used when a noun comes straight after the number. Five, six and a hundred shorten before any noun; ten, twelve and fifteen only before a few time words.

Everywhere else, use the full form. Here's how that works out, with five, six and a hundred:

Full form: pump, chwech, cant

Short form: pum, chwe, can

Masculine and feminine

Only two, three and four have a separate feminine form, used with feminine nouns. They also differ in what they do to the next word:

• The noun after a number stays singular: tair cath is "three cats", not tair cathod.
• The feminine forms carry on inside bigger traditional numbers: tair ar ddeg (13), pedair ar ddeg (14), dwy ar bymtheg (17), dwy ar hugain (22).
• Mil (thousand) is feminine, so two thousand is dwy fil (mil), and three thousand tair mil.
• "Year" is a special case worth knowing: un flwyddyn (blwyddyn), dwy flynedd (blynedd), pum mlynedd (blynedd)… The whole list is in Welsh mutations.

The old way and the new way

Traditional Welsh numbers count partly in fifteens and twenties, so the teens and the tens are built in a way that surprises most learners: eighteen is "two nines", and eighty is "four twenties". The decimal system (simply "one ten one", "two tens") was introduced to make counting easier, especially in school maths.

Both are correct and both are in everyday use. You'll often meet the decimal numbers first, but the traditional ones are everywhere when telling the time, and you'll hear them from many first-language speakers. Your course will tell you which to learn first.

• In the traditional numbers, ar means "on": un ar ddeg is "one on ten". It causes a soft mutation, which is why deg becomes ddeg (deg) and pymtheg becomes bymtheg (pymtheg). Before a vowel, ugain takes an h: un ar hugain (ugain).
• In the decimal numbers, dau ddeg has the soft mutation that dau always causes, and five and six use their short forms: pum deg, chwe deg.
• With a traditional number, the noun can sit in the middle: un plentyn ar ddeg (eleven children). With a decimal number, use o and the plural: un deg un o blant (plant).

First, second, third: ordinals

Most ordinals end in -fed or -ed and come before the noun. Cyntaf (first) is the odd one out: it comes after the noun, like an adjective. Here they are with llyfr (book, masculine) and gwers (lesson, feminine):

• Third and fourth have feminine forms: trydydd → trydedd, pedwerydd → pedwaredd. The rest look the same for both genders.
• With a feminine noun, the ordinal mutates after y, and the noun after it mutates too: y drydedd (trydedd) wers (gwers). With a masculine noun nothing changes: y trydydd llyfr.
• Ail (second) mutates the noun after it, whatever its gender: yr ail lyfr (llyfr).
• Cyntaf behaves like any adjective: it mutates after a feminine noun: y wers gyntaf (cyntaf), but y tro cyntaf (the first time).
• Dates use the masculine ordinals: y cyntaf o Fawrth (Mawrth) (the first of March, St David's Day).
• One you'll see often: yr unfed ganrif (canrif) ar hugain, the twenty-first century, built just like un ar hugain, with the noun in the middle.

Common questions

Why are there two ways of counting in Welsh?

Traditional Welsh counts partly in twenties and fifteens: 18 is deunaw (two nines), 40 is deugain (two twenties). The decimal system (un deg un, dau ddeg…) was brought in to make counting simpler, especially for maths. Both are correct, and both are used: many learners meet the decimal system first and the traditional numbers when telling the time.

Do Welsh numbers have masculine and feminine forms?

Only two, three and four: dau and dwy, tri and tair, pedwar and pedair. Use the feminine form with a feminine noun: dwy gath, tair cath, pedair cath. The ordinals third and fourth have feminine forms too: trydedd and pedwaredd.

What does deunaw mean?

Deunaw is the traditional Welsh for eighteen. It literally means "two nines". In the decimal system, eighteen is un deg wyth.