How much caffeine is in Starbucks Royal English Breakfast Tea?
A Grande (16 fl oz) Starbucks Royal English Breakfast Tea 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?
Had at 3 pm, about 14 mg is still in you at an 11 pm bedtime. That should not affect most people’s sleep.
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Sizes
| Size | Volume | Caffeine | mg per fl oz |
|---|---|---|---|
| Short | 8 fl oz (237 ml) | 40 mg | 5.0 |
| Tall | 12 fl oz (355 ml) | 40 mg | 3.3 |
| Grande shown above | 16 fl oz (473 ml) | 40 mg | 2.5 |
| Venti | 20 fl oz (591 ml) | 40 mg | 2.0 |
Source: starbucks.com · checked 10 Nov 2026
Latest time to drink it
For an 11 pm bedtime, a Grande (16 fl oz) Starbucks Royal English Breakfast Tea 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 | 5:05 pm | Any time | Any time |
| 10 pm | 6:05 pm | Any time | Any time |
| 11 pm | 7:05 pm | Any time | Any time |
| Midnight | 8:05 pm | Any time | Any time |
| 1 am | 9:05 pm | Any time | Any time |
For a Grande (16 fl oz) Starbucks Royal English Breakfast Tea, 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 Royal English Breakfast Tea 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 after | 3 hours | 6 hours | 9 hours | 12 hours |
|---|---|---|---|---|
| Still in you | 28 mg | 19 mg | 12 mg | 8.1 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 Royal English Breakfast Tea is stronger than 59% of the 38 teas we track, by caffeine per serving.
Per fluid ounce (2.5 mg) it is stronger than 50% of them.
To reach 400 mg in a day you would need about 10 of these.
Less caffeine
- Honest Tea Mint Green Tea 35 mg, 16.9 fl oz bottle
- Oolong Tea 30 to 40 mg, 6 fl oz cup
- Snapple Tea 30 mg, 16 fl oz bottle
More caffeine
- Kombucha 41 mg, 12 fl oz bottle
- Yorkshire Gold 43 mg, 200 ml mug, brewed 5 min
- Dona Masala Chai Concentrate 45 mg, 1 serving
Same caffeine: Starbucks Earl Grey Tea.
FAQ
Is Starbucks Royal English Breakfast Tea high in caffeine?
It is moderate. A Grande (16 fl oz) Starbucks Royal English Breakfast Tea 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 Royal English Breakfast Tea?
A Short (8 fl oz) Starbucks Royal English Breakfast Tea has 40 mg of caffeine, the same as than a Grande (16 fl oz) Starbucks Royal English Breakfast Tea.
How much caffeine is in a Venti Starbucks Royal English Breakfast Tea?
A Venti (20 fl oz) Starbucks Royal English Breakfast Tea has 40 mg of caffeine, the same as than a Grande (16 fl oz) Starbucks Royal English Breakfast Tea.
Can I drink Starbucks Royal English Breakfast Tea at night?
For most people, yes: even late in the evening a Grande (16 fl oz) Starbucks Royal English Breakfast Tea stays under 50 mg at an 11 pm bedtime.
How long does the caffeine in Starbucks Royal English Breakfast Tea 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 Royal English Breakfast Tea have more caffeine than a cup of coffee?
No. A Grande (16 fl oz) Starbucks Royal English Breakfast Tea has 40 mg; an 8 fl oz cup of coffee has 95 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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