How Much Caffeine Is in Coffee?

If you’ve ever wondered why one cup of coffee makes you feel ready to conquer the world, while another barely moves the needle, you’re not imagining it. Caffeine levels in coffee can vary a lot, even when the cup size looks the same.

So how much caffeine is actually in coffee? Let’s break it down in a simple, useful way.

The Quick Answer: Average Caffeine in Coffee

On average, an 8oz cup of brewed coffee contains about:

☕ 80–120mg of caffeine

But that’s just the starting point. Depending on the coffee type and brewing method, caffeine can range from as low as 30mg to well over 300mg per serving.

Caffeine by Coffee Type (Common Drinks)

Here are typical caffeine ranges you’ll see in popular coffee styles:

Brewed Coffee (Drip)

• An 8oz serving typically contains about 80 to 120mg of caffeine.

• A 12oz serving typically contains about 120 to 180mg of caffeine.

• A 16oz serving typically contains about 160 to 240mg of caffeine.

Espresso

• A single shot (about 1oz) typically contains about 60 to 75mg of caffeine.

• A double shot typically contains about 120 to 150mg of caffeine.

Espresso is more concentrated, but it’s usually served in smaller portions.

Cold Brew

• A 12oz serving typically contains about 150 to 250mg of caffeine.

• A 16oz serving typically contains about 200 to 300mg or more.

Cold brew often has the most caffeine because it’s brewed strong and steeped for a long time.

Instant Coffee

• An 8oz serving typically contains about 30 to 90mg of caffeine.

Instant tends to be lower caffeine than most brewed coffee.

Decaf Coffee

• An 8oz serving typically contains about 2 to 15mg of caffeine.

Decaf is not caffeine-free — it just contains a very small amount.

Why Caffeine Levels Vary So Much

Coffee isn’t like soda where the caffeine is standardized. Coffee is natural, and caffeine content depends on several factors.

1) Bean Type: Arabica vs Robusta

Arabica beans have a smoother flavor and less caffeine. Robusta beans have a bolder, more bitter taste and about twice the caffeine. Most specialty coffee is Arabica, while many strong commercial blends include Robusta.

2) Roast Level (Light vs Dark Roast)

This one surprises people.

Light roast often has slightly MORE caffeine than dark roast — by volume.

Why? Dark roast coffee beans are roasted longer, becoming less dense. If you measure coffee by scoops (volume), you may use fewer grams of dark roast than light roast.

But if you measure by weight (grams), caffeine levels are usually very similar.

3) Grind Size

A finer grind extracts more caffeine faster. A coarser grind extracts more slowly. That’s why espresso, which uses a fine grind, delivers a strong caffeine hit quickly.

4) Brew Method

Some methods extract more caffeine than others. French press and drip coffee tend to be moderate to high. Espresso has a high concentration. Cold brew is often the highest per serving.

5) Brew Time

Longer brewing time generally means: more caffeine extracted Cold brew is steeped for 12–24 hours — that’s a big reason it’s so strong.

How Much Caffeine Is Too Much?

According to widely accepted guidelines, most healthy adults can safely consume up to about 400mg of caffeine per day.

That’s roughly 3 to 5 cups of coffee depending on strength.

But sensitivity varies. Some people feel jittery after one cup, while others can drink four cups and feel fine.

Signs You’ve Had Too Much Caffeine

If you’re overdoing it, your body usually tells you. Common signs include jitteriness or shakiness, fast heartbeat, anxiety, upset stomach, trouble sleeping, headaches, or caffeine crashes.

If you’re experiencing these regularly, try cutting back or switching to half-caff.

The Bottom Line

A typical cup of coffee has about 80 to 120mg of caffeine, but the real number depends on the coffee type, bean variety, roast level, brew method, and serving size.

If you want to control your caffeine intake, the best thing you can do is pay attention to brew style and serving size, because those two factors make the biggest difference.