How much caffeine is in chocolate cake?

One slice (150 g) of chocolate cake has 11 mg of caffeine.

You would need about 9 of these to equal a cup of brewed coffee (95 mg).

Source: USDA FoodData Central · checked 10 Nov 2026

When did you have it?

Had at 3 pm, about 3.7 mg is still in you at an 11 pm bedtime. That should not affect most people’s sleep.

Bedtime

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Sizes

Size	Weight	Caffeine	Per 100 g
1 slice (150 g) shown above	150 g	11 mg	7 mg
1 cupcake (90 g)	90 g	6.3 mg	7 mg

Source: USDA FoodData Central · checked 10 Nov 2026

Latest time to eat it

For an 11 pm bedtime, one slice (150 g) of chocolate cake stays under the 50 mg most people sleep fine with, even late in the evening. The table works it out for other bedtimes and for how sensitive you are: it is the latest time to start one so that the caffeine left stays under the line all night.

Bedtime	Very sensitive under 25 mg	Average under 50 mg	Not very sensitive under 100 mg
9 pm	Any time	Any time	Any time
10 pm	Any time	Any time	Any time
11 pm	Any time	Any time	Any time
Midnight	Any time	Any time	Any time
1 am	Any time	Any time	Any time

For one slice (150 g) of chocolate cake, average clearance (half-life 5 h), 8 hours of sleep. "Any time" means even one at bedtime stays under the line.

How long it lasts

The caffeine from one slice (150 g) of chocolate cake peaks in your blood about 75 minutes after you start it, at roughly 9 mg. Half of it is gone in about 5 hours for an average adult; that ranges from roughly 3 to 7 hours, and longer in pregnancy or with some medicines.

Time after	3 hours	6 hours	9 hours	12 hours
Still in you	7.4 mg	4.9 mg	3.2 mg	2.1 mg

So one had at 3 pm leaves about 3.7 mg at 11 pm. How long caffeine lasts explains the curve.

How it compares

Chocolate cake is stronger than 31% of the 37 foods we track, by caffeine per serving.

To reach 400 mg in a day you would need about 38 of these.

Less caffeine

Hershey's Milk Chocolate Bar 10 mg, 1 bar
Chocolate Muffin 9 mg, 1 large muffin
Semisweet Chocolate Chips 9 mg, 1 serving

More caffeine

Chocolate Ice Cream 11 mg, 1 large cup
Chocolate Milkshake 11 mg, 1 cup
Black Forest Cake 12 mg, 1 slice

FAQ

Is chocolate cake high in caffeine?

No, it is low. One slice (150 g) of chocolate cake has 11 mg, which is 11% of the 95 mg in an 8 fl oz cup of brewed coffee.

How much caffeine is in 1 cupcake of chocolate cake?

One cupcake (90 g) of chocolate cake has 6.3 mg of caffeine.

Can I eat chocolate cake at night?

For most people, yes: even late in the evening one slice (150 g) of chocolate cake stays under 50 mg at an 11 pm bedtime.

How long does the caffeine in chocolate cake last?

It peaks about 75 minutes after you start it. Of the 11 mg, about 4.9 mg is still in you 6 hours later and 2.1 mg after 12 hours, for an average adult with a 5-hour half-life.

Does chocolate cake have more caffeine than a cup of coffee?

No. One slice (150 g) of chocolate cake has 11 mg; an 8 fl oz cup of coffee has 95 mg.

Method and limits

The caffeine figure comes from USDA FoodData Central and the other sources listed above; recipes, brewing and batches vary, so a real serving can differ. The curves use a standard one-compartment model with an average 5-hour half-life and a sleep-friendly line of 50 mg; your own body may clear caffeine faster or slower. How it works has the details.

These are estimates for information, not medical advice.