Mahjong Score Calculator (Riichi)
An easy-to-use tool to calculate points for Japanese Riichi Mahjong hands.
Hand Value
Payment distribution chart
What is a Mahjong Calculator?
A mahjong calculator is a digital tool designed to simplify the often-complex process of scoring a winning hand in Mahjong, specifically in the Japanese Riichi variant. Instead of manually calculating points based on fan and fu, a player can input these values to get an instant, accurate score. This is invaluable for beginners who are still learning the scoring tables and for experienced players who want to speed up the game. Our calculator determines the total points for both “Ron” (winning from an opponent’s discard) and “Tsumo” (winning by drawing the tile yourself), factoring in whether the winner is the dealer or not.
The Mahjong Calculator Formula and Explanation
The core of Japanese Mahjong scoring revolves around two key units: Fan and Fu. The points are not linear but grow exponentially.
Primary Formula
The basic point value of a hand is calculated with the following formula:
Base Points = Fu * 2^(2 + Fan)
This base value, however, is capped at certain levels for hands of 5 fan or more. These are called “limit hands.”
- Mangan: 3-4 Fan (or specific conditions). Base Points capped at 2000.
- Haneman: 6-7 Fan. Base Points capped at 3000.
- Baiman: 8-10 Fan. Base Points capped at 4000.
- Sanbaiman: 11-12 Fan. Base Points capped at 6000.
- Yakuman: 13+ Fan or a special Yakuman hand. Base Points capped at 8000.
After finding the base points, payments are determined by the winner’s status (Dealer or Non-Dealer) and the win type (Ron or Tsumo). All payments are rounded up to the nearest 100.
| Variable | Meaning | Unit | Typical Range |
|---|---|---|---|
| Fan (Han) | Scoring patterns in the hand. Each ‘fan’ doubles the hand’s value. | Fan | 1 – 13+ |
| Fu | “Mini-points” from melds, pairs, and waits. | Fu | 20 – 110 |
| Dealer Status | Whether the winner is the dealer (East seat). Dealers receive and pay more. | Boolean | Dealer / Non-Dealer |
| Win Type | How the winning tile was acquired (Ron or Tsumo). | Enum | Ron / Tsumo |
Practical Examples
Example 1: Non-Dealer Ron
A player who is not the dealer wins by Ron with a hand worth 3 Fan and 40 Fu.
- Inputs: Fan=3, Fu=40, Dealer=No, Win Type=Ron
- Base Points Calculation: 40 * 2^(2 + 3) = 40 * 2^5 = 40 * 32 = 1280.
- Payment: As a non-dealer Ron, the discarder pays 4 * Base Points. So, 4 * 1280 = 5120 points. Rounded up to the nearest 100, the payment is 5200 points.
- Result: This is a common and important score to learn. For more details on scoring, you can explore resources on mahjong strategy.
Example 2: Dealer Tsumo
The dealer wins by Tsumo with a hand that qualifies as a Haneman (e.g., 6 Fan).
- Inputs: Fan=6, Fu=30 (Fu doesn’t matter for limit hands), Dealer=Yes, Win Type=Tsumo
- Base Points Calculation: Since the hand is 6 Fan, it’s a Haneman. The base points are automatically 3000.
- Payment: As a dealer Tsumo, each of the three other players pays 2 * Base Points. So, 3000 * 2 = 6000. Each player pays the winner 6000 points.
- Result: The dealer receives a total of 18000 points. Mastering these limit hands is a key part of understanding the rules of mahjong.
How to Use This Mahjong Calculator
Using this calculator is simple and quick. Follow these steps to get your hand’s score:
- Enter Fan Value: Type the total number of Fan (or Han) your hand is worth into the first input field.
- Enter Fu Value: In the second field, enter the total Fu, rounded up to the nearest 10 (e.g., 32 Fu becomes 40). For 7 pairs, Fu is always 25. For Pinfu, it’s 20 (Tsumo) or 30 (Ron).
- Select Dealer Status: Check the “I am the Dealer” box if you were the East player for the round.
- Choose Win Type: Select “Ron” if you won from an opponent’s discard or “Tsumo” if you drew the winning tile yourself.
- Review Results: The calculator will instantly display the primary payment value, along with intermediate calculations for Base Points and payment distributions for both Ron and Tsumo scenarios. The chart will also update to visualize the payments.
Key Factors That Affect Mahjong Score
The final score of a hand is influenced by several critical factors. Understanding them is essential for anyone wanting to move beyond using a mahjong calculator and score for themselves. For a deeper dive, consider our guide on advanced mahjong scoring.
- Fan (Han): The most significant factor. Each fan typically doubles the value of the hand. They are awarded for specific patterns (Yaku).
- Fu: While less impactful than Fan, Fu provides the base multiplier for non-limit hands. It is calculated from melds, the pair, and the winning wait.
- Dealer Status: The dealer (also known as Oya) receives approximately 1.5 times more points on a win and pays approximately 1.5 times more on a loss compared to non-dealers (Ko).
- Win Type (Ron vs. Tsumo): A “Ron” win means the discarder pays the full amount. A “Tsumo” (self-draw) win splits the payment among all three opponents, which is often more lucrative, especially for the dealer.
- Limit Hands (Mangan, etc.): Once a hand reaches 5 Fan, the Fu calculation becomes irrelevant. The hand’s value jumps to a fixed “limit” score, such as Mangan, Haneman, or the ultimate Yakuman.
- Dora/Ura-Dora: Dora are bonus tiles that add 1 Fan each but do not count as a Yaku. They can dramatically increase a hand’s value but can only be counted if the hand already has at least one Yaku. This is a topic covered in our mahjong tile guide.
Frequently Asked Questions (FAQ)
A: A hand of 5 Fan is called a Mangan. It has a fixed base value of 2000 points, regardless of the Fu. Our mahjong calculator handles this automatically.
A: Fan are for specific, valuable patterns (Yaku) and act as doublers. Fu are “mini-points” for the hand’s structure (sets, pair, wait). Fan has a much larger impact on the final score.
A: Yes, in Riichi Mahjong, a winning hand must have at least one Fan from a Yaku (a valid scoring pattern). Dora do not count towards this minimum. Checking our list of yaku patterns can be very helpful.
A: A Yakuman is a “limit hand” of the highest order, typically worth 13+ Fan or composed of a very rare, specific pattern. It has a base value of 8000 points, leading to a massive 32,000 (non-dealer) or 48,000 (dealer) point payout.
A: In Riichi Mahjong scoring, Fu is always rounded up to the nearest 10, except for a base of 20 (for Pinfu Tsumo) or 25 (for Seven Pairs). Our mahjong calculator applies this rounding rule.
A: No, this calculator is specifically for Japanese Riichi Mahjong. American, Chinese, and other variants have very different scoring systems.
A: The payment is split. The dealer pays 2 * Base Points, and the other two non-dealers each pay 1 * Base Points (all rounded up to the nearest 100).
A: Fu calculation is complex. You get a base of 20 Fu for winning, then add points for melds (e.g., 8 for a closed triplet of terminals/honors), your pair, and your wait. It’s a topic that deserves its own guide, but our calculator handles it so you don’t have to.
Related Tools and Internal Resources
If you found our mahjong calculator useful, you might also be interested in these resources:
- Complete Guide to Mahjong Yaku: A full list of all scoring patterns with Fan values.
- Mahjong Discard Strategy: Learn what tiles to discard to improve your hand and defense.
- Introduction to Riichi Mahjong: A beginner’s guide to the rules and flow of the game.