What's the standard size for a business card?

The standard size for a business card in the United States is 3.5 inches by 2 inches (89 mm by 51 mm). In many other countries, such as those in Europe, the standard size is often slightly larger at 3.3 inches by 2.1 inches (85 mm by 55 mm). These dimensions ensure that business cards fit easily into wallets and cardholders. Custom sizes are also popular, but the standard sizes are widely recognized and accepted.