Mahjong Rules Tools
Free calculators and practice tools for American Mahjong. Use them at the table or at home, then go Pro to save your games and track your group.
- Free to use, no sign-up
- Built for American Mahjong
- Works on your phone
Unofficial fan tools, not affiliated with the National Mah Jongg League. Record-keeping only: no wagers are accepted and no money is moved.
All tools
Joker Rule Checker
FreeDescribe a situation and get a plain-English answer on whether a Joker move is legal.
Open toolPayout Calculator
Free + ProWork out what each player pays or collects for a hand at your table’s stakes.
Pro adds: self-draw vs. discard, jokerless bonuses, dead hands and full table settlement.
Open toolScorekeeper and Group Tracker
Free + ProRecord every hand of game night and keep a running total for each player.
Pro adds: saved groups, lifetime stats, running balances and a shareable standings page.
Open toolCharleston Assistant
Free + ProEnter your starting tiles and get pass suggestions with the reasoning behind them.
Pro adds: both Charlestons, the courtesy pass and aggressive or conservative pass styles.
Open toolDaily Challenge
Free + ProA new starting hand every day. Choose your pass, then see how your pick compares.
Pro adds: the archive of past challenges and your score history.
Open toolProbability Calculator
FreeYour chances of drawing the tile you need over the next few turns.
Open toolPrintable Generator
FreeScore sheets, house-rules cards and payout cards, ready to print for your table.
Open toolLeague Scheduler
Free + ProSeat rotations for a single session with five to eight players.
Pro adds: multi-week schedules and multiple tables.
Open toolMahjong Rules Tools Pro
For the person who runs the weekly game. Everyone at your table can see the standings, and one organizer keeps the history.
- Saved groups and full game history
- Running balances across sessions
- Shareable standings page for your group
- Advanced payouts: self-draw vs. discard, jokerless bonuses, dead hands
- Charleston Assistant with aggressive and conservative pass styles
- Daily Challenge archive and score history
- Multi-week league schedules for several tables
Pro
Pricing will be announced at launch. Join the waitlist to hear first.
No payment details needed. By joining, you agree to get emails from Mahjong Rules about Pro, new tools and Mahjong tips. Unsubscribe anytime.
Scorekeeper and Group Tracker: what each level includes
| Feature | Free | Free account | Pro |
|---|---|---|---|
| Play a full game night | Yes | Yes | Yes |
| Running totals in the session | Yes | Yes | Yes |
| Saved groups | No | 1 group | Unlimited |
| Lifetime stats | No | Last 5 games | Full history |
| Balances across sessions | No | No | Yes |
| Shareable standings page | No | No | Yes |
Common questions
What is free and what is Pro?
The core calculators and reference tools are free to use with no sign-up. Pro is for people who run a regular game: saved groups, full history, balances across sessions, shareable standings, and deeper options in the Payout Calculator, Charleston Assistant, Daily Challenge and League Scheduler.
Do I need an account to use the tools?
No. You can use every free tool without signing in. A free account (email only) lets you save one group and see your last five games.
Do these tools use the NMJL card?
No. These tools do not use or include the NMJL card. Where a tool needs a number, such as the value of a hand, you enter it yourself from whatever card your table plays.
Are these tools affiliated with the National Mah Jongg League?
No. These are unofficial fan tools made by Mahjong Rules. The NMJL card and its rules belong to the National Mah Jongg League.
Do the tools handle money?
No. They do the arithmetic your table has already agreed on. No wagers are accepted and no money is moved.
Will the calculators match my table’s house rules?
Rules and payouts vary from group to group, so default settings are examples. Check the options against your table’s rules before you start.
What happens to my game data?
Free tools keep your game in your browser. If you create an account, we store your email and any groups you save.
When does Pro open, and how much will it cost?
Pro is not open yet, and pricing will be announced at launch. Join the waitlist and we will let you know when it opens.
Free Mahjong Cheat Sheet
Printable quick reference for NMJL beginners: Charleston steps, passing directions and game flow reminders.
Download Free PDFPlay a full game online
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