In Ironbound, trade and physical mass are anchored by a universal standard coin: the Silver Penny (sp)¹⁾. For the sake of convenience, the copper penny (cp) is also occasionally used; there are ten copper pence to the silver penny.

While political borders shift and local rulers mint their own regional currencies, commerce across the realm relies on a baseline standard maintained not through brute force, but through sheer ubiquity and institutional trust.

The silver penny serves a dual mechanical purpose in the rules:

1. As Currency (sp): The standard medium of exchange for equipment, services, and trade goods.
2. As a Unit of Mass: The baseline measurement for weighing small, precious, or standardized items (such as gems, rare metals, and specific spell components) where exactness matters.

The absolute authority of the standard penny is preserved by a widespread, pan-regional organization (such as a dominant mercantile guild, a ubiquitous temple network, or a historic banking cartel) with a presence in nearly every major settlement and trade hub.

• The Master Scale: Official outposts of this institution maintain a verified reference coin or master-weight.
• Universal Acceptance: Because merchants universally trust this institution's verification, standard-weight coinage is accepted across regional boundaries, bypassing the need for complex, arbitrary exchange rates.

Third-party publishers and Game Masters should define the specific organization, deity, or merchant syndicate that holds this role within their respective campaigns.