How to spell 30 30 is spelled thirty in English. Hear it & practice → On a check To write $30.00 on a check, the words line reads: Thirty and 00/100 Full check-writing guide → Related numbers3 three 40 forty 1 one 10 ten 100 one hundred 1,000 one thousand Spelling guidesMoney amountsHow to write dollars in words.Writing a checkStep-by-step for US checks.Ordinals (1st, 2nd…)First, second, third, and beyond.All guidesDates, phones, fractions, decimals… ← 29All numbers31 →