How much caffeine is in Red Bull Sugarfree?

An 8.4 fl oz can of Red Bull Sugarfree has 80 mg of caffeine.

That's about three quarters of a cup of brewed coffee, and 20% of the 400 mg a day the FDA cites for most healthy adults.

Source: redbull.com · checked 10 Nov 2026

When did you have it?

Had at 3 pm, about 28 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	Volume	Caffeine	mg per fl oz
8.4 fl oz can shown above	8.4 fl oz (248 ml)	80 mg	9.5
12 fl oz can	12 fl oz (355 ml)	114 mg	9.5
16 fl oz can	16 fl oz (473 ml)	151 mg	9.4
20 fl oz can	20 fl oz (591 ml)	198 mg	9.9

Source: redbull.com · checked 10 Nov 2026

Latest time to drink it

For an 11 pm bedtime, most people should finish an 8.4 fl oz can of Red Bull Sugarfree by about 7:05 pm. 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	12:05 pm	5:05 pm	Any time
10 pm	1:05 pm	6:05 pm	Any time
11 pm	2:05 pm	7:05 pm	Any time
Midnight	3:05 pm	8:05 pm	Any time
1 am	4:05 pm	9:05 pm	Any time

For an 8.4 fl oz can of Red Bull Sugarfree, 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 an 8.4 fl oz can of Red Bull Sugarfree peaks in your blood about 75 minutes after you start it, at roughly 68 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	56 mg	37 mg	24 mg	16 mg

So one had at 3 pm leaves about 28 mg at 11 pm. How long caffeine lasts explains the curve.

How it compares

Red Bull Sugarfree is stronger than 5% of the 41 energy drinks we track, by caffeine per serving.

Per fluid ounce (9.5 mg) it is stronger than 14% of them.

To reach 400 mg in a day you would need about 5 of these.

Less caffeine

V Energy Drink 78 mg, 250 ml can
Thums Up Charged 73 mg, 250 ml bottle

More caffeine

Dutch Bros Rebel Energy Drink 115 mg, Medium iced
Clean Cause Yerba Mate 120 mg, 12 fl oz can
Uptime Energy 142 mg, 12 fl oz bottle

Same caffeine: Red Bull, Red Bull Editions.

FAQ

Is Red Bull Sugarfree high in caffeine?

It is moderate. An 8.4 fl oz can of Red Bull Sugarfree has 80 mg, which is 84% of the 95 mg in an 8 fl oz cup of brewed coffee.

How much caffeine is in 12 fl oz can of Red Bull Sugarfree?

A 12 fl oz can of Red Bull Sugarfree has 114 mg of caffeine, 34 mg more than an 8.4 fl oz can of Red Bull Sugarfree.

How much caffeine is in 20 fl oz can of Red Bull Sugarfree?

A 20 fl oz can of Red Bull Sugarfree has 198 mg of caffeine, 118 mg more than an 8.4 fl oz can of Red Bull Sugarfree.

Can I drink Red Bull Sugarfree at night?

Earlier is better. Had at 7 pm, it leaves about 49 mg in an average adult at an 11 pm bedtime. The latest time for an 11 pm bedtime is about 7:05 pm.

How long does the caffeine in Red Bull Sugarfree last?

It peaks about 75 minutes after you start it. Of the 80 mg, about 37 mg is still in you 6 hours later and 16 mg after 12 hours, for an average adult with a 5-hour half-life.

Does Red Bull Sugarfree have more caffeine than a cup of coffee?

No. An 8.4 fl oz can of Red Bull Sugarfree has 80 mg; an 8 fl oz cup of coffee has 95 mg.

Method and limits

The caffeine figure comes from redbull.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.