A typical single shot of espresso (about 1 ounce or 30 milliliters) contains approximately 63 to 75 milligrams of caffeine. This amount can vary depending on factors such as the type of coffee bean (Robusta beans have more caffeine than Arabica), the roast level (lighter roasts tend to have slightly more caffeine), grind size, tamping pressure, and water temperature used during extraction

. To summarize:

• Average caffeine in a single espresso shot: 63–75 mg
• Range can vary roughly from 30 mg up to 100 mg or slightly more depending on preparation and bean type

• A double shot (2 ounces) typically contains about 125–150 mg of caffeine

Despite espresso's smaller volume compared to brewed coffee, it has a higher caffeine concentration per ounce, which is why its caffeine effect can feel stronger even though a standard 8-ounce cup of coffee usually contains more total caffeine (around 95–96 mg)