Daily Caffeine Ceiling
The adult reference is 6 mg per kilogram with an overall cap of 400 mg, so 65 kg gives 390 mg — just inside. A single Americano runs about 120 mg.
Your numbers
Caffeine ceiling
390mg
Cups of coffee
3.3
Milligrams per kg
6mg
What it means
390 mg a day — about 3.3 of these cups. The adult ceiling does not rise above 400 mg.
Formula
Caffeine ceiling = Weight (kg) × 6
In pregnancy the figure drops to 200 mg, and for adolescents it is 2.5 mg per kilogram. Energy drinks, chocolate and some painkillers carry caffeine too.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Weight (kg) (kg)The second weight you are comparing against. | 65 | 10 and up |
| Caffeine (mg) (mg)Caffeine taken in; a single Americano runs about 120 mg. | 120 | 1 and up |
Step by step
Quick reference table
Results when only Weight (kg) (kg) changes and everything else stays put.
| Weight (kg) (kg) | Caffeine ceiling (mg) | Cups of coffee | Milligrams per kg (mg) |
|---|---|---|---|
| 32.5 | 195 | 1.6 | 6 |
| 48.8 | 293 | 2.4 | 6 |
| 65 | 390 | 3.3 | 6 |
| 97.5 | 400 | 3.3 | 4.1 |
| 130 | 400 | 3.3 | 3.1 |
What each result means
| Result | At default values |
|---|---|
| Caffeine ceiling (mg)The daily caffeine ceiling; for adults it stops at 400 mg. | 390 |
| Cups of coffeeThat ceiling expressed in cups of the strength you entered. | 3.3 |
| Milligrams per kg (mg)Milligrams per kilogram — used for drugs and caffeine ceilings. | 6 |
Common mistakes
In pregnancy the figure drops to 200 mg, and for adolescents it is 2.5 mg per kilogram. Energy drinks, chocolate and some painkillers carry caffeine too.
Glossary
- Weight (kg)
- The second weight you are comparing against.
- Caffeine (mg)
- Caffeine taken in; a single Americano runs about 120 mg.
- Caffeine ceiling
- The daily caffeine ceiling; for adults it stops at 400 mg.
- Cups of coffee
- That ceiling expressed in cups of the strength you entered.
- Milligrams per kg
- Milligrams per kilogram — used for drugs and caffeine ceilings.
Frequently asked questions
Q. How is Daily Caffeine Ceiling calculated?
Caffeine ceiling = Weight (kg) × 6 — The adult reference is 6 mg per kilogram with an overall cap of 400 mg, so 65 kg gives 390 mg — just inside. A single Americano runs about 120 mg.
Q. Can you walk through an example?
With Weight (kg) 65kg, Caffeine (mg) 120mg, the answer is Caffeine ceiling 390mg.
Q. What do I need to enter?
Enter Weight (kg), Caffeine (mg). The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Weight (kg) (kg) moves the answer to Weight (kg) (kg) 32.5 → Caffeine ceiling (mg) 195 and Weight (kg) (kg) 130 → Caffeine ceiling (mg) 400. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
In pregnancy the figure drops to 200 mg, and for adolescents it is 2.5 mg per kilogram. Energy drinks, chocolate and some painkillers carry caffeine too.
Related calculators
These calculators help you understand health figures; they do not replace diagnosis or prescription. See a clinician if you have symptoms.