Learn Welsh Numbers
This page covers modern decimal Welsh (Cyfrif degol y Gymraeg) — the system taught in primary schools today. The traditional vigesimal system (deugain, hanner cant) is still used for time, dates and age, but the decimal system is what learners memorise first and what the quiz tests.
1–10: the building blocks
Memorise these — everything else is built from them:
- 1 = un
- 2 = dau
- 3 = tri
- 4 = pedwar
- 5 = pump
- 6 = chwech
- 7 = saith
- 8 = wyth
- 9 = naw
- 10 = deg
Two of these shorten before another number word: pump → pum and chwech → chwe (apocope) before deg, cant or mil.
11–19: un deg X
The decimal system uses un deg (“one ten”) plus the digit:
- 11 = un deg un
- 12 = un deg dau
- 13 = un deg tri
- 14 = un deg pedwar
- 15 = un deg pump
- 16 = un deg chwech
- 17 = un deg saith
- 18 = un deg wyth
- 19 = un deg naw
20–99: tens with mutations
Each tens word is the digit + deg, but 2 triggers a soft mutation (d → dd) and 5 and 6 apocopate:
- 20 = dau ddeg (soft mutation: d → dd)
- 30 = tri deg
- 40 = pedwar deg
- 50 = pum deg (pump → pum)
- 60 = chwe deg (chwech → chwe)
- 70 = saith deg
- 80 = wyth deg
- 90 = naw deg
Compounds add the unit after a space:
- 21 = dau ddeg un
- 47 = pedwar deg saith
- 99 = naw deg naw
Quick check: 22, 56, 88?
22 dau ddeg dau · 56 pum deg chwech · 88 wyth deg wyth
Hundreds
The word for 100 is cant. Multipliers trigger different mutations:
- 100 = cant
- 200 = dau gant (soft mutation: c → g)
- 300 = tri chant (aspirate mutation: c → ch)
- 400 = pedwar cant
- 500 = pum cant
- 600 = chwe chant (aspirate mutation)
- 700 = saith cant
- 800 = wyth cant
- 900 = naw cant
Combine with tens and units after a space:
- 134 = cant tri deg pedwar
- 365 = tri chant chwe deg pump
Thousands & millions
Mil is a feminine noun, so 2–4 use the feminine forms (dwy, tair, pedair) and trigger soft mutation:
- 1,000 = mil
- 2,000 = dwy fil
- 3,000 = tair mil
- 4,000 = pedair mil
- 5,000 = pum mil
- 6,000 = chwe mil
- 10,000 = deg mil
- 100,000 = can mil (cant → can before mil)
- 1,000,000 = miliwn
Larger compounds chain together:
- 1,234 = mil dau gant tri deg pedwar
- 5,000,000 = pum miliwn
Common mistakes
- Forgetting apocope: it’s pum deg not “pump deg”, and chwe deg not “chwech deg”.
- Soft vs. aspirate mutation: dau triggers soft (dau gant), but tri and chwe trigger aspirate (tri chant, chwe chant).
- Feminine concord with mil: use dwy/tair/pedair before mil, not dau/tri/pedwar.
- Decimal vs. vigesimal: in this quiz, dau ddeg = 20, not ugain. The vigesimal system you may hear in older speech (deugain = 40, hanner cant = 50) isn’t used here.