Same source + target will be avoided when possible.
Earn calculus points by reaching score & survival milestones in each mode. Spend them in the 🧮 Shop.
This will permanently erase all achievements, stats, unlocked bases, rewards, and cosmetics. This cannot be undone.
A number appears on screen written in a source base. Your job is to convert it and type the answer in the target base. You have a timer per round.
Pick your own source and target bases, timer, and round count. The most flexible mode.
All standard bases → Base 10. Five rounds, default timer. Good warm-up.
100 seconds on a global clock. Answer as many rounds as you can before time runs out.
You have HP instead of rounds. Being off by N costs N HP. Survive as long as possible.
The target base is hidden. You must figure it out from the answer alone. No hints.
Survival rules with Nightmare's hidden target. The hardest standard mode.
Uses only the cursed bases — mysterious number systems that don't follow the normal rules. Unlocked after discovering all cursed bases.
Free mode. Choose exactly which conversion to drill. No scores, no pressure, no stats recorded.
Bases 17–21 are hidden by default. Use them as source or target during a game to discover them. Some extra-special bases are even more hidden — keep exploring.
• In Nightmare, the correct base is revealed after every round — use that to narrow down future guesses.
• In Survival, prioritise accuracy over speed — one bad guess can cost you the run.
• Time Rush rewards fast and reasonably accurate answers — a +80 in 4 seconds beats a +100 in 14.
• The Practice mode is the best way to get comfortable with an unfamiliar base before playing seriously.
Small numbers — great for learning a new base.