Korean uses two number systems side by side, and choosing the wrong one is a classic learner mistake. This free tool spells any whole number in both: the Sino-Korean set (일, 이, 삼) for dates, money, and large counts, and the native Korean set (하나, 둘, 셋) for counting objects, ages, and hours.
How it works
Sino-Korean numbers are positional, but grouped by ten thousand (만) rather than thousand. The tool reads the number in four-digit groups and attaches the large-place names 만, 억, 조, and 경 to each group. Within a group it uses 천 (1000), 백 (100), 십 (10) and the digit words 일–구, omitting an explicit 일 before 십/백/천 where Korean does.
Native Korean is built from the ones words (하나–아홉) and the tens words (열, 스물, 서른 … 아흔). The tool composes a value below 100 by joining the tens word and the ones word, for example 47 → 마흔일곱.
Tips and notes
Use Sino-Korean for the year, month, day, minutes, prices, phone numbers, and anything large; use native Korean for the hour, age, and counting discrete things with a counter such as 개, 명, or 마리. Remember the contracted counter forms: 한, 두, 세, 네, and 스무 replace 하나, 둘, 셋, 넷, and 스물 immediately before a measure word. Above 99, switch to Sino-Korean. All calculation happens locally in your browser.