A typical 8-ounce (237 ml) cup of black tea contains about 40 to 60 milligrams of caffeine on average, with some variation depending on factors like brewing time, tea type, and leaf quality. The caffeine content can range from as low as 14 milligrams up to 90 or even 100 milligrams in some cases. Generally, a standard cup has around 47 milligrams of caffeine

. Key points about caffeine in black tea:

• Brewing time affects caffeine: longer steeping (e.g., 5 minutes) increases caffeine content, while shorter brewing times yield less caffeine

• Black tea contains more caffeine than green tea (20–45 mg per cup) but less than coffee, which typically has 95–200 mg per 8-ounce cup

• Decaffeinated black tea usually contains only 2–5 mg of caffeine per cup

• The caffeine strength in black tea is considered moderate compared to coffee

In summary, expect about 40-60 mg of caffeine in a standard cup of black tea, but this can vary based on preparation and tea variety.