A typical 8 oz (240 ml) cup of black tea has roughly 40–70 mg of caffeine, with many sources putting the average around 45–50 mg per cup.

Quick Scoop

  • Most black teas: about 40–70 mg caffeine per 8 oz cup.
  • Average often quoted: around 47–50 mg per cup.
  • Real-world range: roughly 14–90 mg depending on leaf type, brew time, and strength.
  • That’s less than a standard cup of coffee (about 95 mg), but more than most green and white teas.

What Changes the Caffeine?

  • Brew time: Longer steeping (4–5+ minutes) pulls more caffeine into the cup.
  • Leaf type: Stronger styles like Assam and some breakfast blends are usually on the higher end of the range.
  • Form: Fine-cut tea bags can release caffeine faster than many larger loose‑leaf teas.
  • Serving size: “A cup” here means 8 oz; big mugs (12–16 oz) will naturally give you more total caffeine.

Simple rule of thumb

If you think in coffee terms: one 8 oz black tea is usually about half the caffeine of a typical 8 oz coffee.

Information gathered from public forums or data available on the internet and portrayed here.