What's In Your Wallet?

D&D has a money problem. Not because adventurers carry too much of it, but because the basic math behind it collapses the second anyone asks a practical question.

According to standard fifth-edition rules, 50 coins weigh one pound, regardless of metal. That sounds clean at first glance, but if a copper piece weighs the same as a gold piece, their physical sizes have to be completely wild. Pure gold is nearly twice as dense as silver and more than twice as dense as copper. To make a copper coin weigh the same as a gold coin, that copper piece would need to be the size of a coaster, while the gold piece would look like a tiny metal flea.

Alternatively, if every coin is the same physical size, a bag of gold will weigh double a bag of copper. Trying to balance bulk scales, counting troughs, and encumbrance becomes a headache for players and DMs alike.

If your world features an organized merchant class, they would never operate on hand-waving logic. Banking requires standardization, security, and speed. Here is how a sophisticated Guild of Merchants actually solves the physics of coinage.

The Standard Planchet Solution

To make currency both easily stackable in chests and easily weighable in bulk, the Guild mints every denomination on identical planchets:

• Diameter: ~1 inch
  
  
• Thickness: 0.06 inches
  
  
• Weight: 6 grams (75 coins per pound)
  
  
• Edge: Reeded (grooved to instantly reveal clipping or filing)
  
  

Because every coin shares the exact same size and weight, merchants do not need to sort loose coin before taking a total. They toss a mixed sack onto a beam scale. If it weighs 100 pounds, there are exactly 7,500 coins inside.

If they need a fast visual check, 50 loose coins in a pouch take up exactly half a cup of volume. One hundred coins fill a cup. Sixteen hundred coins fill a gallon jug.

Engineered Metallurgy

Ancient and medieval mints were not ignorant of chemistry; they deliberately alloyed metals to adjust durability and appearance. The Guild uses engineered alloys to ensure every coin hits the exact 6-gram target while maintaining distinct visuals:

• Sovereign (Platinum Alloy): Platinum blended with a light base metal. Worth 25 Gold (2,500 Copper).
  
  
• Crown / Royal (Gold Alloy): Standard gold tempered for durability. Worth 1 Gold (100 Copper).
  
  
• Noble (Silver Alloy): Silver weighted down with dense base elements. Worth 1/10 Gold (10 Copper).
  
  
• Guilder (Premium Bronze): Dark, rich bronze alloy. Worth 1/20 Gold (5 Copper). The distinct dark brown tone prevents fraudsters from gold-plating it to fake a Royal, and it rings with a high pitch when dropped on a stone counter.
  
  
• Common (Hardened Copper): Copper alloyed for wear resistance. Worth 1/100 Gold (1 Copper).
  
  

Table Reference: Bulk & Volume

Coin Count	Weight	Loose Volume
50 Coins	0.67 lbs	1/2 Cup
75 Coins	1.0 lb	3/4 Cup
100 Coins	1.33 lbs	1.0 Cup
1,000 Coins	13.33 lbs	10 Cups (~2.5 Quarts)
7,500 Coins	100.0 lbs	Standard Wooden Coin Chest

This system keeps tabletop encumbrance simple, gives merchants believable operational tools (counting troughs, beam scales, reeded edges), and grounds the economy in actual physical logic.

Based on the rigorous specifications and metallurgical logic established by the Merchant Guild, here is how the standardized currency appears. Each coin maintains the exact 1-inch diameter and 0.06-inch thickness, engineered to weigh exactly 6 grams (75 coins per pound).

From left to right:

1. The Sovereign (Platinum Alloy): The high-value 25-Crown coin, minted from a dense, silver-white platinum alloy. Note the clean, consistent reeded edge.

2. The Crown / Royal (Gold Alloy): The base unit of the economy. A standardized gold alloy tempered for durability.

3. The Noble (Silver Alloy): The standard silver piece (1/10 Crown), weighted with dense base elements to hit the 6-gram target.

4. The Guilder (Premium Bronze): The dark, rich bronze 5-copper coin. The Merchant Guild selected this distinct alloy and dark tone specifically to prevent anyone from plating it and trying to pass it off as gold.

5. The Common (Copper Alloy): The copper unit (1/100 Crown), hardened to survive heavy circulation.