How to Play & Learn
Welcome to OC - Online Calculator. Here are the rules, mechanics, and process to level up your rank while converting units.
Core Mechanics
Every time you convert a value, whether it's length, weight, or temperature, it gets recorded in your history. By performing conversions regularly, you can unlock achievements and rise through the ranks.
- Convert any unit and it will be saved in your history automatically.
- Use different units to unlock the Unit Master achievement.
- Mark frequently used conversions as favorites for quick access.
Gems & Rewards
Gems are the primary currency and reward system. You can earn Gems by participating in activities. Keep converting to collect more!
Daily Challenges
Every day at midnight, a new Daily Challenge is available. It tasks you with converting a specific value between two units.
Claim your challenge reward manually in the sidebar to add the Gems to your account. Don't miss out, as challenges reset daily!
Streaks
A Streak represents how many consecutive days you have used the app and performed at least one conversion.
- Convert at least once every 24 hours to keep your streak alive.
- If you miss a day, your streak will reset to 0.
Ranks & Progression
Your rank is determined by the total number of conversions you've performed across all categories. Try to reach the highest rank!
Learn FAQ
Do I need an account to use converters?
No. You can use all core converters without an account. Signing in unlocks progress tracking, achievements, streaks, and favorites across devices.
How are streaks counted?
A streak increases when you complete at least one conversion in a 24-hour window. If you skip a day, the streak resets and starts again at 1 on your next conversion.
What is the fastest way to level up?
Use multiple categories, complete daily challenges, and save frequently used conversions to favorites. This combination helps you earn rewards and rank up consistently.