Riichi Mahjong Calculator

Calculate your hand’s score, understand yaku, and simplify scoring in Riichi Mahjong.

Riichi Mahjong Hand Scoring

Enter the details of your Riichi Mahjong hand to calculate the score.

Common Yaku Combinations and Points

Common Riichi Mahjong Yaku

Yaku (Name)	Han	Base Points (25 Fu)	Example Scenario
Riichi	1	1000	Declaring ready in a standard hand.
Tanyao (All Simples)	1	1000	Hand composed only of 2-8 tiles.
Pinfu	1	1000	A specific structure of waits and no apparent pair Fu.
Dora	1 per Dora tile	1000 per Dora	Holding the current Dora indicator tile.
Tsuuiisou (All Honors)	6	12000	Hand composed entirely of honor tiles.
Chinitsu (Full Flush)	5 or 6	12000 or 16000	Hand composed of only one suit.
Dai Su Rinkan (Big Three Dragons)	2	2000	Melding all three dragon triplets/quad.

What is a Riichi Mahjong Calculator?

A Riichi Mahjong calculator is an essential tool designed to simplify the complex scoring system of Japanese Mahjong, specifically the Riichi variant. It allows players to input key details about their winning hand and receive an accurate calculation of the score, typically expressed in Fan (Han) and Fu, which then translates into points. Understanding the score is crucial for strategic gameplay, knowing how much to bet or how much you owe, and developing effective hand-building techniques. Whether you’re a beginner struggling with the intricacies of Fan and Fu, or an experienced player looking for a quick verification, a Riichi Mahjong calculator provides immediate feedback and helps demystify the scoring process. It’s particularly useful for online Mahjong or in situations where manual calculation might be time-consuming or error-prone. This tool aids in learning common yaku combinations and their associated point values, ultimately enhancing the overall Mahjong experience.

Who Should Use a Riichi Mahjong Calculator?

Anyone playing Riichi Mahjong can benefit from this calculator. This includes:

• Beginner Players: Those new to the game who find the scoring rules daunting.
• Intermediate Players: Players looking to speed up their scoring and better understand the impact of different yaku and fu combinations.
• Online Mahjong Players: For quick, accurate scoring in digital games.
• Study Groups: To analyze hands and learn scoring mechanics collectively.
• Tournament Players: For rapid score calculation during competitive play, though official tournaments often have specific scoring assistants.

Common Misconceptions about Riichi Mahjong Scoring

Several misconceptions surround Riichi Mahjong scoring:

• “More Han always means a much higher score”: While Han is critical, Fu significantly impacts the base score, especially for lower Han hands. A hand with high Fu can sometimes score more than a hand with slightly more Han but low Fu.
• “All hands with Riichi are 1 Fan, 1000 points”: This is a simplification. While declaring Riichi grants 1 Han, the total score depends heavily on the base yaku in the hand and the Fu value.
• “Dealer always gets double points”: The dealer’s score is indeed doubled for a win (both Tsumo and Ron), but the base points calculated are the same; it’s the payout that’s doubled. For a Ron, the non-dealer pays double the base value to the dealer. For a Tsumo, the dealer pays double the base value to the winner, and non-dealers pay the base value.
• “Fu is always calculated manually”: While manual calculation is possible, standard Fu values (20, 25, 30, 40) are common for specific hand structures, and calculators streamline this.

Riichi Mahjong Scoring Formula and Mathematical Explanation

The score in Riichi Mahjong is determined by a combination of Fan (Han) and Fu. The general process involves calculating base points from Fu, then adjusting them based on Han, and finally considering who won the hand (dealer or non-dealer) and how (self-draw or discard claim).

Step-by-Step Calculation

1. Determine Fu: Calculate the base Fu for the hand. Common sources of Fu include:
   • Pair of honor tiles (except dragons): 2 Fu
   • Pair of dragon tiles: 0 Fu
   • Pair of wind tiles matching round/prevalent wind: 4 Fu
   • Pair of wind tiles not matching: 2 Fu
   • Waiting for a single tile (e.g., 234, wait for 3; 223, wait for 2 or 3): 2 Fu
   • Edge wait (e.g., 23, wait for 4): 2 Fu
   • 34, wait for 2 or 5 (open): 2 Fu
   • 444, wait for 4 (open): 2 Fu
   • Concealed triplet/quad of honor tiles: 8 Fu (triplet) / 16 Fu (quad)
   • Concealed triplet/quad of numbered tiles: 4 Fu (triplet) / 8 Fu (quad)
   • 444 (concealed): 4 Fu
   • Minimum 20 Fu for a closed hand, 25 Fu if it includes a pair of winds matching the round/prevalent wind or a single-wait/edge-wait.
   • A winning tile claimed from a discard (Ron) adds 10 Fu if the hand was previously closed (not declared Riichi or ready).
2. Calculate Base Points: The base points are calculated from the Fu value, rounded up to the nearest 10.
   • If Fu is less than 10, it’s ignored.
   • If Fu is 10 or more, round up to the nearest 10.
   • Base Points = (Rounded Fu) × 2^{(Number of Fan + 2)}

   The calculator uses this formula, adjusting for common Fu values.

3. Apply Fan (Han): The Fan value determines the exponent in the base points calculation. Higher Fan values significantly increase the score.
4. Determine Final Score:
   • Non-Dealer (Shimocha/Oicha): The calculated base points are the points awarded.
   • Dealer (Oya): The calculated base points are doubled.
5. Pinfu and Riichi Bonus:
   • A hand with Pinfu and 1 Fan (no other yaku) is typically worth 1000 points if the winner is a non-dealer, and 1500 points if the winner is the dealer (assuming 25 Fu base).
   • A declared Riichi hand that wins by Ron (or Tsumo) also adds 1000 points (non-dealer) or 1500 points (dealer) to the score, in addition to the hand’s base value. This is sometimes referred to as the “1000 point bonus” or “1500 point bonus”.
6. Yakitori Bonus: If Yakitori is achieved, it adds 1 Fan to the hand.
7. Rounded Score: Scores are often rounded up to the nearest 100 points for non-dealers, and nearest 500 points for dealers. Our calculator provides the exact calculated points and then a commonly accepted rounded value.

Variable Explanations

Variable	Meaning	Unit	Typical Range
Fan (Han)	A measure of the hand’s rarity and difficulty. Each yaku (scoring condition) adds Han.	Integer	1 to 13 (or higher for multiple yaku and special hands)
Fu	A measure of the hand’s structure and wait type.	Integer	20 to 110+ (typically 20, 25, 30, 40)
Round Wind	The current wind of the round (e.g., East 1, South 1). Affects scoring if it’s also the prevalent wind.	Enum (East, South, West)	East, South, West
Prevalent Wind	The wind of the current seat. Affects scoring if it’s also the round wind.	Enum (East, South, West)	East, South, West
Dealer	Indicates if the winning player is the dealer (Oya).	Boolean (Yes/No)	Yes, No
Self-Draw (Tsumo)	Indicates if the winning tile was self-drawn.	Boolean (Yes/No)	Yes, No
Yakitori	A bonus yaku if the hand includes all three dragon tiles and both wind tiles.	Boolean (Yes/No)	Yes, No
Base Points	The initial point value calculated from Fu and the lowest Han multiplier.	Points	Starts at 1000 for 25 Fu, 1 Fan.
Final Score	The total points awarded or owed, considering all factors.	Points	Varies greatly.

Practical Examples (Real-World Use Cases)

Let’s look at a couple of common scenarios to see how the Riichi Mahjong calculator works.

Example 1: Simple Riichi Hand (Non-Dealer)

Scenario: You are playing as a non-dealer. You declare Riichi on your first pass, and your hand consists of a sequence 345 of Bamboo, a triplet of 777 of Circles, and a pair of East winds. You win by Ron on a 6 of Bamboo. Your hand is closed (Riichi declared).

Input:

• Fan (Han): 2 (1 for Riichi, 1 for Tanyao)
• Fu: 30 (2 for wait, 4 for East wind pair, 4 for concealed triplet of 7s, 20 base = 30)
• Round Wind: East
• Prevalent Wind: South
• Yakitori: No
• Self-Draw (Tsumo): No (Ron)
• Dealer: No

Calculator Output (Estimated):

• Main Result: 2000 points
• Base Points: 1000
• Final Score (Rounded): 2000
• Points (vs Dealer): Not applicable (won by Ron)
• Points (from Non-Dealer): 2000

Interpretation: This is a standard Riichi hand. The 2 Han (Riichi + Tanyao) and 30 Fu result in 1000 base points. Since it’s a non-dealer winning by Ron, the hand is worth 2000 points, paid by the player who discarded the winning tile. This is a respectable score for a simple hand.

Example 2: Dealer Wins with a Half-Flush

Scenario: You are the dealer. You have managed to form a hand consisting of 111, 222, 333, 444, and a pair of 7s of Circles. You win by self-draw (Tsumo) on the 7 of Circles. This hand is a Chinitsu (Full Flush).

Input:

• Fan (Han): 6 (1 for Full Flush, 1 for Pinfu-like structure, 1 for Pair of 7s, 1 for four triplets, 1 for dealer bonus, 1 for Yakitori – assuming all winds and dragons are present. Note: specific yaku might overlap or require more complex calculation. For simplicity, let’s assume 6 Han). For a proper calculation, actual yaku would be listed. A common Chinitsu is 5 or 6 Han. Let’s use 6 for a strong hand.
• Fu: 40 (Base 20, Pair of 7s = 2, Four triplets = 0, Concealed = 0. Wait on 7s for 777 -> 2 Fu. Assume a 25 Fu base minimum due to being a closed hand. A typical scenario for a full flush could yield 40 Fu)
• Round Wind: East
• Prevalent Wind: East
• Yakitori: Yes (for example purposes, adding 1 Han)
• Self-Draw (Tsumo): Yes (Tsumo)
• Dealer: Yes

Calculator Output (Estimated):

• Main Result: 48000 points
• Base Points: 12000 (assuming 40 Fu and 6 Han)
• Final Score (Rounded): 48000
• Points (vs Dealer): Not applicable (dealer win)
• Points (from Non-Dealer): Not applicable (dealer win)

Interpretation: This is a very strong hand, a Full Flush (Chinitsu) with Yakitori, won by the dealer via Tsumo. The high Han value (6) combined with a decent Fu (40) results in a substantial score. As the dealer, the base points are doubled (12000 base points) to 24000, and this is paid by each of the three non-dealers. However, typically, dealer Tsumo hands round up significantly. For a 6 Han hand, the dealer’s score is often capped at Yakuman (32000 points) or calculated higher depending on specific rulesets. Our calculator provides a potential calculation point (e.g., 48000 if not capped). A more realistic value for a dealer winning a high-Han hand like this is often a Yakuman (32,000 points). This example highlights how quickly scores can escalate with powerful yaku.

How to Use This Riichi Mahjong Calculator

Using the Riichi Mahjong calculator is straightforward. Follow these steps to get your hand’s score:

Step-by-Step Instructions

1. Identify Your Hand’s Details: Before using the calculator, you need to know the key components of your winning hand:
   • Fan (Han): Count the number of scoring conditions (yaku) present in your hand.
   • Fu: Determine the Fu value based on your hand’s structure and wait.
   • Round and Prevalent Winds: Note the current round wind and the wind for your seat.
   • Dealer Status: Are you the dealer?
   • Winning Method: Did you win by self-draw (Tsumo) or by claiming a discard (Ron)?
   • Yakitori: Did your hand qualify for Yakitori?
2. Input the Values: Enter the identified details into the corresponding fields on the calculator:
   • Input the total Fan and Fu values.
   • Select the correct Round Wind and Prevalent Wind from the dropdowns.
   • Choose whether you are the Dealer.
   • Select whether it was a Self-Draw (Tsumo) or Ron.
   • Indicate if your hand included Yakitori.
3. Calculate: Click the “Calculate Score” button.

How to Read Results

After clicking “Calculate Score”, the calculator will display:

• Main Result: This is the primary calculated score for your hand, often rounded. It represents the points awarded for a non-dealer win or the points each non-dealer pays to the dealer.
• Intermediate Values:
  • Base Points: Shows the score before doubling for the dealer or specific rounding.
  • Final Score (Rounded): The commonly accepted final score, often rounded up.
  • Points (vs Dealer): If you are a non-dealer winning by Ron, this shows the points you receive from the player who discarded.
  • Points (from Non-Dealer): If you are a non-dealer winning by Tsumo, this shows the points you receive from each of the other players. If you are the dealer winning by Tsumo, this shows the total points the non-dealers pay you.
• Formula Used: A brief explanation of the scoring logic.

Decision-Making Guidance

The results can inform your gameplay:

• Aggressiveness: A high score indicates a valuable hand, encouraging you to push for a win. A low score might suggest playing more defensively.
• Risk Assessment: Understanding the score value helps in deciding whether to continue a risky hand or to discard safely.
• Learning Tool: Use the calculator to verify scores of hands you’ve played or seen, reinforcing your understanding of yaku and fu combinations.
• Strategy Refinement: By seeing how different Fan and Fu values translate to points, you can refine your hand-building strategies.

Don’t forget to use the “Copy Results” button to save or share your calculated score!

Key Factors That Affect Riichi Mahjong Results

Several elements significantly influence the final score of a Riichi Mahjong hand. Understanding these factors is key to mastering the game’s scoring system.

1. Fan (Han): This is the primary multiplier for your score. Each distinct yaku (scoring condition) adds Han. Common yaku like Riichi, Tanyao, Pinfu, or specific triplets/sequences contribute 1 Han, while rarer hands like Chinitsu (Full Flush) or Kokushi Musou (Thirteen Orphans) contribute much more. Higher Han dramatically increases the score.
2. Fu: While Han dictates the multiplier, Fu determines the base value. Fu is awarded for specific hand structures, waits, and pairs. A closed hand always starts with a minimum Fu (usually 25 or 30). Certain waits (like single-tile or edge waits) and pairs (like wind pairs matching the round/prevalent wind) add Fu. A higher Fu, especially combined with higher Han, leads to a significantly larger score.
3. Dealer Status (Oya): The dealer’s score is always doubled. This means winning as the dealer is generally more profitable than winning as a non-dealer, especially for high-scoring hands. Conversely, if a non-dealer wins, the dealer pays double the non-dealer’s share.
4. Winning Method (Tsumo vs. Ron):
   • Tsumo (Self-Draw): When you draw the winning tile yourself, all three opponents pay you.
   • Ron (Discard Claim): When you claim a tile discarded by an opponent, only that opponent pays you. This is generally less profitable than Tsumo for the winner, but it ensures the hand ends immediately.

   The calculator distinguishes these as they affect the payout structure.

5. Round and Prevalent Winds: If the pair in your hand consists of the same wind tile as the current round wind OR the prevalent wind for your seat, it earns bonus Fu (4 Fu). If it’s a pair of the *other* wind, it earns 2 Fu. This impacts the total Fu, and thus the score.
6. Yakitori: This special yaku adds 1 Han if your hand contains all three dragon tiles and both wind tiles (East and South, or East, South, West). It’s a relatively easy Han to aim for in certain situations, boosting your score.
7. Special Hands & Limits (Yakuman): Extremely rare and difficult hands, like Chinitsu with high Han, Kokushi Musou, or Daisūshii, can reach or exceed 13 Han. These hands are often declared a Yakuman (or multiple Yakuman), which has a fixed, very high point value (typically 32,000 points for a non-dealer, 48,000 for a dealer), often capping the score regardless of exact Han/Fu calculation.
8. Additional Bonuses (e.g., Riichi Bonus): A declared Riichi hand that wins also often grants a bonus point payout (e.g., 1000 points for a non-dealer winner, 1500 for a dealer winner), on top of the hand’s calculated score. This calculator aims to incorporate common bonuses where applicable.

Frequently Asked Questions (FAQ)

Q1: What is the difference between Fan (Han) and Fu?

A: Fan (Han) represents the rarity and complexity of a hand, acting as a multiplier. Fu represents the specific structure and wait of the hand, determining the base point value. Both are essential for calculating the final score.

Q2: How is the minimum Fu determined?

A: A closed hand (Riichi or won concealed) generally has a base Fu of 20 or 25. If the winning pair is a wind matching the round or prevalent wind, or if the hand has a specific type of wait (single, edge, or open triplet/quad), the Fu increases. Tsumo hands are typically valued higher in Fu if they contain certain conditions.

Q3: Does the calculator handle all possible Riichi Mahjong yaku?

A: This calculator focuses on core scoring elements like Fan, Fu, winds, and dealer status. While it doesn’t list every single obscure yaku individually, it allows you to input the *total* Fan value, encompassing all your yaku. Specific yaku like Yakitori are included as specific inputs.

Q4: What is Yakuman?

A: Yakuman is a special category for extremely rare and high-scoring hands, typically equivalent to 13 Fan or more. They have a fixed, high point value (usually 32,000 points for non-dealer, 48,000 for dealer) and often cannot be combined with other yaku to exceed their value.

Q5: How do I calculate Fu for a complex hand?

A: Calculating Fu manually can be intricate. It involves summing points for your pair, your melds (if any), your wait type, and adding base Fu. For closed hands, the minimum is typically 25 Fu. This calculator uses common Fu values for input, but understanding the breakdown is key for learning.

Q6: Can I use this calculator for other Mahjong variants?

A: This calculator is specifically designed for the rules of Riichi Mahjong (Japanese Mahjong). Scoring systems vary significantly between different Mahjong variants (e.g., Chinese Official, American Mahjong), so it would not be accurate for those.

Q7: What if my hand has multiple same-value yaku?

A: In Riichi Mahjong, you count the total number of Fan (Han). For example, if you have Riichi (1 Han) and Tanyao (1 Han), your total is 2 Han. You don’t add them independently if they are for the same part of the hand structure, but rather sum up distinct scoring conditions. Some hands like Chinitsu can grant 5 or 6 Han depending on circumstances.

Q8: Does the calculator account for abortive draws?

A: This calculator focuses on scoring a *completed* winning hand. It does not calculate scores or penalties related to abortive draws (e.g., four players declaring Riichi, nine-tile draws, etc.), which result in no score changes or specific penalties.