If you reach for iced tea as an afternoon pick-me-up, you might be wondering how much caffeine you're actually getting. The answer depends on the type of tea, how long you steep it, and how you brew it. Here is everything you need to know.

Caffeine in Iced Tea by Type

Not all iced tea is created equal when it comes to caffeine. Here is a general breakdown per 250ml (8oz) serving:

Tea Type	Caffeine (approx.)
Black iced tea	40–70 mg
Green iced tea	20–35 mg
White iced tea	15–30 mg
Oolong iced tea	30–50 mg
Herbal iced tea	0 mg
Matcha iced tea	50–70 mg

These are estimates — actual caffeine content varies by brand, tea origin, and brewing conditions.

Black Iced Tea: The Highest Caffeine Option

Black tea is the most caffeinated of the true teas. A standard glass of black iced tea contains roughly 40–70mg of caffeine — about half the amount in a cup of coffee. Assam and Ceylon varieties tend to be on the higher end; Darjeeling is typically lower.

If you are making a strong concentrate and diluting it, your final caffeine level will be lower than a straight-brewed cup.

Green Iced Tea: Moderate and Steady

Green tea contains less caffeine than black tea — typically 20–35mg per glass. It also contains L-theanine, an amino acid that promotes calm focus and smooths out the caffeine effect. Many people find green tea gives them a gentler, more sustained energy boost without the jitteriness of coffee.

Herbal Iced Tea: Naturally Caffeine-Free

Herbal teas — chamomile, hibiscus, peppermint, rooibos, and most fruit blends — contain zero caffeine. They are made from flowers, fruits, and herbs rather than the Camellia sinensis plant, which is the source of caffeine in true teas.

If you want a completely caffeine-free iced tea, herbal blends are your best option. Rooibos in particular makes an excellent iced tea base with a naturally sweet, slightly nutty flavour.

How Brewing Method Affects Caffeine

Hot Brew vs. Cold Brew

Cold brewing extracts caffeine more slowly than hot brewing. A cold-brewed iced tea steeped for 8–12 hours will typically have 20–30% less caffeine than the same tea brewed hot. If you are sensitive to caffeine, cold brewing is a smart choice.

Steep Time

Longer steeping = more caffeine. A black tea steeped for 5 minutes will have noticeably more caffeine than one steeped for 2 minutes. This is why over-steeped tea also tastes more bitter — you are extracting more tannins along with the caffeine.

Tea Bags vs. Loose Leaf

Loose-leaf tea is generally higher quality and can have more consistent caffeine levels. Tea bags often contain smaller, broken leaves (called fannings) that release caffeine quickly. Neither is dramatically higher or lower — the difference is modest.

Caffeine Sensitivity: What to Watch For

If you are sensitive to caffeine, a few practical tips:

• Switch to green or white tea for a gentler effect
• Cold brew your tea to reduce caffeine extraction
• Steep for less time — 2 minutes instead of 5 for black tea
• Choose herbal blends for evening drinks or caffeine-free days
• Avoid matcha iced tea late in the day — it has the highest caffeine of any iced tea

The Bottom Line

A glass of iced tea has significantly less caffeine than coffee, making it a great option for those who want a mild energy boost without the intensity. Black tea gives you the most caffeine, herbal gives you none, and green sits comfortably in the middle. Cold brewing and shorter steep times both reduce caffeine if that is a priority for you.

Now you can sip your next glass with full knowledge of what is in it.