Tools
Free, no sign-up, works on your phone at the table.
25PTS
Payout calculator
Who owes the winner what: discard or self-pick, jokerless or not, at your table's stakes.
3PASSCharleston trainer
Walk through every pass, step by step, with arrows. Right, across, left, and the parts everyone forgets.
152TILESTile chart
All 152 American mahjong tiles: what they're called, how many of each, and what jokers and flowers are for.