CaffeineIQ

How much caffeine is in Starbucks London Fog Latte?

A Grande (16 fl oz) Starbucks London Fog Latte has 40 mg of caffeine.

That's about half a cup of brewed coffee, and 10% of the 400 mg a day the FDA cites for most healthy adults.

Source: starbucks.com · checked 10 Nov 2026

When did you have it?

50 mgBed 11 pm: 14 mg6am9am12pm3pm6pm9pm12am3am

Had at 3 pm, about 14 mg is still in you at an 11 pm bedtime. That should not affect most people’s sleep.

Bedtime

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Sizes

SizeVolumeCaffeinemg per fl oz
Short8 fl oz (237 ml)40 mg5.0
Tall12 fl oz (355 ml)40 mg3.3
Grande shown above16 fl oz (473 ml)40 mg2.5
Venti20 fl oz (591 ml)40 mg2.0

Source: starbucks.com · checked 10 Nov 2026

Latest time to drink it

For an 11 pm bedtime, a Grande (16 fl oz) Starbucks London Fog Latte 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.

BedtimeVery sensitive
under 25 mg		Average
under 50 mg		Not very sensitive
under 100 mg
9 pm5:05 pmAny timeAny time
10 pm6:05 pmAny timeAny time
11 pm7:05 pmAny timeAny time
Midnight8:05 pmAny timeAny time
1 am9:05 pmAny timeAny time

For a Grande (16 fl oz) Starbucks London Fog Latte, 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 a Grande (16 fl oz) Starbucks London Fog Latte peaks in your blood about 75 minutes after you start it, at roughly 34 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 after3 hours6 hours9 hours12 hours
Still in you28 mg19 mg12 mg8.1 mg

So one had at 3 pm leaves about 14 mg at 11 pm. How long caffeine lasts explains the curve.

How it compares

Starbucks London Fog Latte is stronger than 4% of the 90 coffee-shop drinks we track, by caffeine per serving.

Per fluid ounce (2.5 mg) it is stronger than 4% of them.

To reach 400 mg in a day you would need about 10 of these.

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FAQ

Is Starbucks London Fog Latte high in caffeine?

It is moderate. A Grande (16 fl oz) Starbucks London Fog Latte has 40 mg, which is 42% of the 95 mg in an 8 fl oz cup of brewed coffee.

How much caffeine is in a Short Starbucks London Fog Latte?

A Short (8 fl oz) Starbucks London Fog Latte has 40 mg of caffeine, the same as than a Grande (16 fl oz) Starbucks London Fog Latte.

How much caffeine is in a Venti Starbucks London Fog Latte?

A Venti (20 fl oz) Starbucks London Fog Latte has 40 mg of caffeine, the same as than a Grande (16 fl oz) Starbucks London Fog Latte.

Can I drink Starbucks London Fog Latte at night?

For most people, yes: even late in the evening a Grande (16 fl oz) Starbucks London Fog Latte stays under 50 mg at an 11 pm bedtime.

How long does the caffeine in Starbucks London Fog Latte last?

It peaks about 75 minutes after you start it. Of the 40 mg, about 19 mg is still in you 6 hours later and 8.1 mg after 12 hours, for an average adult with a 5-hour half-life.

Does Starbucks London Fog Latte have more caffeine than Red Bull?

No. A Grande (16 fl oz) Starbucks London Fog Latte has 40 mg; an 8.4 fl oz can of Red Bull has 80 mg.

Method and limits

The caffeine figure comes from starbucks.com; 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.

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