Buying Guides July 15, 2026

Mahjong Tile Size Guide: Dimensions for American, Chinese & Japanese Sets

Wei Liang, a Shenzhen mahjong factory owner, breaks down every tile size standard with real mold data — American, Chinese, Japanese, travel, senior, and custom OEM.

By Wei Liang · Founder & Production Lead, Mahjong Market

I run a mahjong tile factory in Shenzhen. Over the past fourteen years I have cut steel molds for tiles ranging from 18mm travel minis to 42mm custom OEM monsters. I have weighed every size on a calibrated bench scale, measured engraving depth with a micrometer, and watched players test each variant across test tables in our showroom. Tile size is the single most overlooked buying decision in mahjong — people fixate on material and color while ignoring the three numbers that determine whether the set actually works for their hands, their racks, and their eyes. This guide covers every standard you need to know.

The numbers that matter

Every mahjong tile has three critical dimensions: width, height, and depth. Width is the measurement across the face — the dimension that determines how many tiles fit on a rack. Height is the vertical measurement from the bottom of the tile to the top, the primary number that affects readability. Depth is the thickness of the tile body, which affects weight and how the tile sits in your hand.

In our factory, I specify these three numbers for every production run. A single millimeter matters. Change the depth by 0.5mm and the per-tile weight shifts by roughly 0.4 grams; multiply that by 166 tiles and the full set changes by 66 grams. Change the height by 3mm and a different rack becomes necessary. Every dimension has consequences downstream — for the case size, the shipping carton, the rack slot spacing, and the player’s comfort.

Standard tile sizes by game variant

Here is the reference data from my production floor, measured on finished tiles after molding and polishing. All measurements in millimeters.

Variant	Width	Height	Depth	Weight per tile	Total tiles
American (standard)	30mm	38mm	10mm	~12.6g (acrylic) / ~9.8g (melamine)	166
Chinese (standard)	25mm	35mm	8mm	~7.2g	144
Japanese Riichi (standard)	26mm	36mm	9mm	~8.5g	136
Japanese Riichi (large)	33mm	38mm	10mm	~11.2g	136
Mini / Travel	20mm	28mm	7mm	~4.1g	166
Senior / Large-print	30mm	33mm	10mm	~10.5g (melamine)	166

American standard

The NMJL specification calls for tiles approximately 30mm wide by 38mm tall by 10mm deep. In imperial units that is roughly 1.2 by 1.5 by 0.4 inches. This is the size we mold most often — roughly 60% of our production volume is American-standard tiles in melamine or acrylic.

At 38mm tall the characters are readable from across a card table. At 10mm deep the tile has enough heft to feel substantial (9.8 grams in melamine, 12.6 grams in acrylic) but not so heavy that a full rack strains your wrists. The 30mm width is driven by rack compatibility — every standard American rack on the market is cut for 30mm wide tiles.

Mold tolerance on our premium line is plus or minus 0.15mm. On our budget wholesale line it relaxes to plus or minus 0.35mm. That 0.2mm difference is invisible to the naked eye, but it determines whether a tile snaps cleanly into a rack slot or wobbles. I recommend asking any manufacturer about their tolerance before buying — a set with plus or minus 0.5mm tolerance will fit poorly on any rack.

Chinese standard

Chinese tiles are smaller: 25mm wide, 35mm tall, and 8mm deep. The tiles weigh roughly 7.2 grams each. The narrower width means you can fit more tiles per rack — standard Chinese racks hold 18 tiles in a single row, versus 13 for American racks.

The height difference (35mm versus 38mm) means Chinese tiles carry smaller characters. This works because Chinese mahjong tiles typically use engraved symbols that are easier to distinguish in a small footprint — dots, bams, and Chinese characters are more visually distinct than the English letters and numbers on American tiles, which need more surface area for legibility.

The depth at 8mm makes Chinese sets significantly lighter. A full 144-tile Chinese set weighs about 1,037 grams — roughly two-thirds of a standard American acrylic set. If you have played both, you notice the difference immediately when stacking the wall. Chinese tiles feel quicker in the hand.

Japanese Riichi standard

Japanese tiles come in two sizes that I mold regularly. The standard competition size is 26mm by 36mm by 9mm, weighing about 8.5 grams. This is designed for the Japanese auto-table distribution and the typical 13-tile Japanese rack. A larger variant runs 33mm by 38mm by 10mm — this is used by players who prefer a more substantial feel and by clubs that cater to older players with vision needs.

Japanese Riichi sets contain 136 tiles (no flowers, no seasons, no jokers). The tile backs are typically solid yellow or black rather than the ivory-white common on American and Chinese sets. The 26mm width is the one to watch — it is strictly narrower than American 30mm tiles, and the racks are not interchangeable. American tiles will not fit on Japanese racks, period.

Mini and travel tiles

Our travel line uses 20mm by 28mm by 7mm tiles weighing 4.1 grams each. That is roughly one-third the weight of an American acrylic tile. A full 166-tile travel set with racks and a compact case ships at about 1.5 kilograms. The smaller dimensions sacrifice some readability — you need good lighting and decent eyesight — but the portability gain is substantial. Our travel American mahjong set uses this size spec.

Senior and large-print tiles

For players who need larger characters, I mold a senior variant at 30mm by 33mm by 10mm with 0.5mm engraving depth instead of the standard 0.3mm. The extra 0.2mm of engraving makes the markings fill better with paint and reflect more light, which improves contrast. I developed this spec after receiving consistent feedback from players in their 70s and 80s who were squinting at their tiles under living room lighting. The 33mm height is 5mm taller than a travel tile but still fits standard American racks.

Our best mahjong set for seniors uses this size spec paired with melamine for the lightest finished weight.

How tile size affects gameplay

Wall building

Tile depth directly affects how a wall stacks. American tiles at 10mm deep produce a stable two-high wall about 20mm thick. Travel tiles at 7mm deep stack less securely — the wall is more likely to collapse during shuffling or if a player bumps the table. Japanese tiles at 9mm fall in between. I recommend 10mm depth as the minimum for confident wall building in a group setting with shuffling. For travel play where walls are smaller and handling is gentler, 7mm is adequate.

Shuffling friction

Tile face area determines how tiles slide against each other during the wash. Larger face area equals more contact surface, which means more friction. American tiles at 30mm by 38mm (1,140 square millimeters of face area) generate significantly more friction during shuffling than Chinese tiles at 25mm by 35mm (875 square millimeters). This is a comfort factor — the larger American tile feels less slippery and is easier to control during a vigorous shuffle. The travel tile’s 20mm by 28mm face (560 square millimeters) can feel too slippery for some players, especially on a smooth mat.

Reading across the table

Tile height is the dominant factor for readability. At 38mm, American tiles are readable from a full arm’s reach across a standard card table. At 28mm, travel tiles require players to lean in slightly. At 20mm — the smallest tiles I have ever molded for a custom order — you need the tiles right in front of you.

The relationship between height and reading distance is roughly linear. A 38mm tile is legible at approximately 1.2 meters under standard indoor lighting. A 28mm tile is legible at about 0.9 meters. If your playing group sits at an unusually large table or plays in dim lighting (restaurants, cruise ship lounges), lean toward taller tiles.

Hand comfort and fatigue

Weight differences compound over a two-hour session. I have timed players picking up, reading, and discarding tiles — the average player handles each tile 30 to 40 times per session. At 12.6 grams per tile (American acrylic), that is roughly 500 grams of cumulative handling per tile. At 4.1 grams (travel), it drops to 164 grams. For players with arthritis or carpal tunnel, the difference is meaningful. Our melamine tiles at 9.8 grams per tile bridge the gap — lighter than acrylic but with the same dimensions and full rack compatibility.

Mold tolerance and quality

I mentioned tolerance briefly above, but it deserves its own section because it is invisible to the buyer. Here is what I track on our production floor:

Production line	Tolerance	Visual consistency	Rack fit
Premium	plus or minus 0.15mm	Identical to the naked eye	Snug, no wobble
Standard wholesale	plus or minus 0.35mm	Minor height variation visible to trained eye	Minor wobble on some racks
Budget / mass market	plus or minus 0.50mm	Noticeable height variation	Frequent wobble

A 0.15mm tolerance requires steel molds re-machined every 8,000 press cycles. A 0.50mm tolerance lets the mold run 25,000 cycles before rework. That cost difference flows through to the retail price. Premium tolerance is worth paying for if you play regularly and want your tiles to feel uniform in the hand.

Our complete American mahjong set deluxe uses the premium 0.15mm tolerance. Our beginner American mahjong set uses the standard 0.35mm line to keep the price accessible.

Engraving depth and visibility

Standard engraving depth is 0.3mm — deep enough to hold paint securely, shallow enough that the mold releases cleanly. For senior sets, I go to 0.5mm. The extra 0.2mm creates a deeper paint well, which catches light from a wider angle and makes characters visible even when a player is looking down at their rack from a slight angle.

I have tested engraving depths from 0.15mm to 0.8mm. Below 0.2mm, the paint wears off within roughly 200 shuffles. Above 0.6mm, the mold release becomes unreliable and the tile surface develops stress marks around the engraved area. 0.3mm is the sweet spot for balance between durability and appearance.

Rack compatibility by tile size

This table is worth saving if you switch between game variants:

Tile type	Width	Compatible rack type
American	30mm	American racks (13 tiles per row)
Chinese	25mm	Chinese racks (18 tiles per row)
Japanese standard	26mm	Japanese racks (13 tiles per row)
Japanese large	33mm	American-style extended racks
Travel	20mm	Travel racks or small Chinese racks

An American tile will not seat properly in a Japanese rack — the 30mm tile is 4mm wider than the rack slot. Forcing it damages both the tile edge and the rack groove. I see this mistake in club photos occasionally: someone brought the wrong set to a Riichi night and is trying to make it work.

For players who regularly switch between American and Chinese play, adjustable racks exist. They are less common but worth tracking down if both games are in your rotation. Our guide to the best mahjong racks covers the adjustable options currently available.

Shipping weight and case size

Tile dimensions determine case dimensions, and case dimensions determine shipping carton size and freight cost. Here is the practical impact:

• American standard (166 tiles, melamine): Set weighs roughly 1.63 kilograms. With a standard hard case and four racks, shipping weight is about 3.8 kilograms. Case dimensions are approximately 38cm by 28cm by 12cm.
• Travel set (166 tiles, mini): Set weighs roughly 680 grams. With a compact case and four short racks, shipping weight is about 1.5 kilograms. Case dimensions are approximately 28cm by 20cm by 8cm.

The freight difference between the two is roughly 60%. This matters if you are ordering internationally or buying wholesale for a club. A pallet of American standard sets ships 200 units. The same pallet ships 480 travel sets. If a club needs 50 sets for a tournament, travel size changes the logistics budget meaningfully.

Custom sizes for OEM buyers

I do custom tooling for brands that want proprietary dimensions. The most common requests are:

• 42mm tall tiles for luxury gift sets, often paired with real gold leaf inlay. These feel closer to domino tiles than standard mahjong tiles. They require custom racks — retail racks max out at about 38mm.
• 15mm deep tiles for weighted luxury sets. The extra mass makes every click and discard feel deliberate. These sets ship in foam-lined wooden cases.
• 22mm wide tiles for compact club sets that need to fit on narrow French card tables.

Custom tooling starts at roughly $4,000 per mold and requires a minimum order of 500 sets. The lead time is 8 to 10 weeks including mold fabrication. For buyers interested in OEM runs, I cover the full process in our custom OEM mahjong buyer guide.

Choosing the right size for your needs

You play American mahjong weekly at a club or community center

30mm x 38mm x 10mm, melamine. The standard American size with the standard material workhorse. Melamine keeps the weight manageable and you will never worry about durability. The tiles fit every rack in the club.

You play at home with friends, 1-2 times per month

30mm x 38mm x 10mm, acrylic. Same dimensions, upgraded material. The brighter sound and translucent finish make home play feel more special, and the 300-cycle scratch resistance is more than enough for light use.

You travel regularly — cruise ships, rentals, flights

20mm x 28mm x 7mm, melamine. The weight and case size difference changes whether mahjong makes the trip. At 4.1 grams per tile you will not notice the set in your bag.

You are buying for a parent or grandparent over 70

30mm x 33mm x 10mm, melamine with 0.5mm engraving. The taller tile and deeper engraving make a genuine difference in readability. I have watched players in their late 70s go from squinting to reading without effort after switching from 28mm travel tiles to 33mm senior tiles.

You play Japanese Riichi competitively

26mm x 36mm x 9mm. This is the standard for tournament play and auto-table compatibility. The second number on the tile back (26mm width) is critical — anything wider and the auto-table pusher will jam.

You want a gift set that feels substantial

30mm x 38mm x 10mm, acrylic, deluxe case. Skip the novelty sizes. The standard American dimensions in premium acrylic with a padded case and matching racks communicates quality without confusing the recipient about compatibility.

Summary reference table

Use case	Width	Height	Depth	Weight	Material	Engraving
American club play	30mm	38mm	10mm	9.8g	Melamine	0.3mm
American home play	30mm	38mm	10mm	12.6g	Acrylic	0.3mm
Chinese standard	25mm	35mm	8mm	7.2g	Melamine	0.3mm
Japanese Riichi	26mm	36mm	9mm	8.5g	Melamine	0.3mm
Travel / portable	20mm	28mm	7mm	4.1g	Melamine	0.3mm
Senior / vision help	30mm	33mm	10mm	10.5g	Melamine	0.5mm

Tile size looks like a small detail on a spec sheet — three numbers buried under the color, material, and case options. In practice, those three numbers determine whether your tiles fit your rack, whether you can read them from the far side of the table, and whether your hands feel sore after the third game. I have run enough production batches across every size on this chart to know that buying the right dimensions matters as much as buying the right material. Get the size right and the rest of the set follows naturally.

If you need more help choosing, our beginner American mahjong set is a good starting point for most home players, and our guide to the differences between American and Chinese mahjong covers the full equipment breakdown by variant.