How much caffeine is in decaf tea?
An 8 fl oz cup of decaf tea has 4 to 6 mg of caffeine.
That's a small fraction of a cup of brewed coffee, and 1% of the 400 mg a day the FDA cites for most healthy adults.
Source: tetleyusa.com · checked 10 Nov 2026
When did you have it?
Had at 3 pm, about 1.8 mg is still in you at an 11 pm bedtime. That should not affect most people’s sleep.
Ranges: the chart uses the middle of the published range (5 mg for this size).
Your whole day, every drink, in the free CaffeineIQ check. The iPhone app is coming soon.
Latest time to drink it
For an 11 pm bedtime, an 8 fl oz cup of decaf 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 | 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 an 8 fl oz cup of decaf 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 an 8 fl oz cup of decaf tea peaks in your blood about 75 minutes after you start it, at roughly 4.3 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 | 3.5 mg | 2.3 mg | 1.5 mg | 1 mg |
So one had at 3 pm leaves about 1.8 mg at 11 pm. How long caffeine lasts explains the curve.
How it compares
Decaf tea is stronger than 0% of the 38 teas we track, by caffeine per serving.
Per fluid ounce (0.6 mg) it is stronger than 3% of them.
To reach 400 mg in a day you would need about 80 of these.
Less caffeine
- Herbal Tea no caffeine
- Starbucks Iced Passion Tango Tea no caffeine
- Starbucks Mint Majesty Tea no caffeine
More caffeine
- GT's Synergy Kombucha 4 to 8 mg, 8 fl oz serving
- AriZona Green Tea 8 to 10 mg, 12 fl oz serving
- Fuze Mango Green Tea 10 mg, 16.9 fl oz bottle
FAQ
Is decaf tea high in caffeine?
No, it is low. An 8 fl oz cup of decaf tea has 4 to 6 mg, which is 5% of the 95 mg in an 8 fl oz cup of brewed coffee.
Can I drink decaf tea at night?
For most people, yes: even late in the evening an 8 fl oz cup of decaf tea stays under 50 mg at an 11 pm bedtime.
How long does the caffeine in decaf tea last?
It peaks about 75 minutes after you start it. Of the 4 to 6 mg, about 2.3 mg is still in you 6 hours later and 1 mg after 12 hours, for an average adult with a 5-hour half-life.
Does decaf tea have more caffeine than a cup of coffee?
No. An 8 fl oz cup of decaf tea has 4 to 6 mg; an 8 fl oz cup of coffee has 95 mg.
Method and limits
The caffeine figure comes from tetleyusa.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.