Numbers: the ultimate barrier for language learners.
From Sino-Korean to Native Korean, time telling, and figures up to 999 trillion.
With ChislOKay, you'll master them all with absolute confidence.

“일, 이, 삼... wait, why is time 하나, 둘, 셋?”
For learners, Korean numbers are often the biggest roadblock. Two distinct numeral systems (Sino-Korean and Native Korean) take more than just reading textbooks to truly grasp.
We bypassed pure theory for intuitive practice and seamless repetition. What started as a niche project has evolved into the ultimate solution for Korean language enthusiasts worldwide—now fully available in English.
‘Chislo’ (Number) + ‘OK’. Because numbers should just be... OK.
Beyond just reading. Immersive audio and precision-timed exams.
Your native language doesn't matter. Featuring a native Korean interface, with English and Russian available right out of the box. Effortless setup.
Generate numbers all the way up to 999,999,999,999,999. From everyday counts to macroeconomic figures from the news, all in one seamless experience.
Reading and hearing are distinct skills. Listen to flawless TTS and respond. Pacing: 🐢 Slow / ▶️ Normal / 🐇 Fast.
“2:30” — hours in Native Korean, minutes in Sino-Korean. We isolated the trickiest patterns into a dedicated, focused mode.
Listen to two numbers and instantly decide which is greater (or lesser). It’s how Korean numbers become second nature.
We strip away the UI to leave only the challenge. Set a timer (e.g., 30 minutes). Review bookmarks and dive deep into mistake analysis afterward.
Any skill level. One-tap configurations.
Minimal interface, maximum focus. Set a timer, start the practice, and get your own mock test.
No logins. No paywalls. Just open your browser and start mastering numbers right now.
Get Started* ChislOKay is an open-source, non-profit project by Fishydino, crafted to support Korean language learners worldwide.