Rhifau | numbers

In Welsh, there are four categories of numbers:

  • Feminine numbers
  • Masculine Numbers
  • Decimal numbers (sometimes called the “modern counting system”)
  • Vigesimal numbers (sometimes called the “traditional/old counting system”

Masculine and feminine numbers only really exist up to 5. We use masculine numbers when quantifying masculine nouns (e.g. dogs) and feminine nouns when quantifying feminine nouns (e.g. cats)

We use the vigesimal number system, which works (broadly speaking) in units of 20s, when we are dealing with numbers involving:

  • weights
  • measurements
  • distances
  • ages
  • dates
  • time


m = masculine

f = feminine

Cardinal = the normal numbers we use when counting

Ordinals= numbers that put things in order, e.g. firstsecondthird.

Numbers in green= Traditional/old/vigesimal system (see above!)

Cardinal Ordinal
0 sero/dim
1 un 1af cynta(f)
2 dau (m)

dwy (f)

2ail ail
3 tri (m)

tair (f)

3ydd trydydd (m)

trydedd (f)

4 pedwar (m)

pedair (f)

4ydd pedwerydd (m)

pedwaredd (f)

5 pum(p) 5ed pumed
6 chwe(ch) 6ed chweched
7 saith 7fed seithfed
8 wyth 8fed wythfed
9 naw 9fed nawfed
10 deg 10fed degfed
11 un ar ddeg

un deg un

11eg unfed ar ddeg
12 deuddeg

un deg dau

12fed deuddegfed
13 tri ar ddeg

un deg tri

13eg trydydd ar ddeg
14 pedwar ar ddeg

un deg pedwar

14eg pedwerydd ar ddeg
15 pymtheg

un deg pump

15fed pymthegfed
16 un ar bymtheg

un deg chwech

16eg unfed ar bymtheg
17 dau ar bymtheg

un deg saith

17eg ail ar bymtheg
18 deunaw

un deg wyth

18fed deunawfed
19 pedwar ar bymtheg

un deg nau

19eg pedwerydd ar bymtheg
20 ugain

dau ddeg

20fed ugeinfed
21 un ar hugain

dau ddeg un

21ain unfed ar hugain
22 dau ar hugain

dau ddeg dau

22ain ail ar hugain
23 tri ar hugain

dau ddeg tri

23ain trydydd ar hugain
24 pedwar ar hugain

dau ddeg pedwar

24ain pedwerydd ar hugain
25 pump ar hugain

dau ddeg pump

25ain pumed ar hugain
26 chwech ar hugain

dau ddeg chwech

26ain chweched ar hugain
27 saith ar hugain

dau ddeg saith

27ain seithfed ar hugain
28 wyth ar hugain

dau ddeg wyth

28ain wythfed ar hugain
29 naw ar hugain

dau ddeg naw

29ain nawfed ar hugain
30 deg ar hugain

tri deg

30ain degfed ar hugain
31 un ar ddeg ar hugain

tri deg un

31ain unfed ar ddeg ar hugain

N.b. It’s not very common to hear traditional (i.e. vigesimal) numbers over 31 being used in spoken Welsh, except when taking about ages.

Mutations and other forms

Click here for information on the mutations.

  • un > soft mutation to singular feminine nouns
    • un gath (one cat)
  • dau and dwy (two)  > soft mutation to nouns, and take a soft mutation when preceded by the definite article y
    • dau fwrdd (two tables)
    • dwy gadair (two chairs)
    • y ddau fwrdd (the two tables)
    • y ddwy gadair(the two chairs)
  • tri (three) > aspirate mutation to nouns
    • tri chi (three dogs)
  • pump (five) becomes pum when followed immediately by a noun
    • pum cath (five cats)
    • pump o gathod (five cats)
  • chwech (six) becomes chwe and causes an aspirate mutation when a singular noun comes immediately after, e.g. chwe chath (six cats)

  • Deg (ten) turns into deng when counting things
    • deng munud (10 minutes)
  • or when it appears in a compound number (i.e. two numbers stuck together)
    • deuddeng mlynedd (12 years).

  • In ordinal numbers larger than 10 the thing being counted is placed between the first and second parts of the number
    • e.g. unfed ganrif ar hugain (21st Century).

Click here to read more about Welsh’s two different number systems. 

Numbers over 31

Cardinal Cymraeg Ordinal Cymraeg
32 deuddeg ar hugain
tri deg dau
32ain deuddegfed ar hugain
33 tri ar ddeg ar hugain
tri deg tri
33ain tri ar ddegfed ar hugain
34 pedwar deg ar hugain
tri deg pedwar
34ain pedwar degfed ar hugain
35 pymtheg ar hugain
tri deg pump
35ain pymthegfed ar hugain
36 un ar bymtheg ar hugain
tri deg chwech
36ain un ar bymthegfed ar hugain
37 dau ar bymtheg ar hugain
tri deg saith
37ain dau ar bymthegfed ar hugain
38 deunaw ar hugain
tri deg wyth
38ain deunawfed ar hugain
39 pedwar ar bymtheg ar hugain
tri deg naw
39ain pedwerydd ar bymtheg ar hugain
40 deugain
pedwar deg
40fed deugainfed
50 hanner cant
pum deg
50fed hanner canfed
60 trigain
chwe deg
60fed trigainfed
70 deg a thrigain
saith deg
70fed degfed a thrigain
80 pedwar ugain
wyth deg
80fed pedwar ugainfed
90 deg a phedwar ugain
naw deg
90fed naw deg
degfed a phedwar ugain
100 cant 100fed canfed
101 cant ac un cant ac un
102 cant a dau cant a dau
120 cant ac ugain
cant dau ddeg
cant dau ddeg
200 dau gant 200fed dau ganfed
300 tri chant 300fed tri chanfed
400 pedwar cant 400fed pedwar canfed
500 pum cant 500fed pum canfed
600 chwe chant 600fed chwe chanfed
700 saith cant 700fed saith canfed
800 wyth cant 800fed wyth canfed
900 naw cant 900fed naw canfed
1,000 mil 1000fed milfed
10,000 deng mil deng milfed
100,000 mwnt
can mil
can milfed
1 million miliwn miliyenfed
1 billion biliwn biliyenfed