**Try using our caffeine calculator to estimate caffeine intake and its potential overdose effects on your body using “Caffeine Dosage (mg/kg) = Total Caffeine Consumed (mg) / Body Weight (kg)” formula.**

A person weighing **70 kg** who consumes two cups of coffee (**200 mg caffeine**) and a can of energy drink (**80 mg caffeine**) can use a **caffeine overdose calculator** to determine:

**Total caffeine intake**: 280 mg**Caffeine per kg of body weight**: 4 mg/kg**Estimated time until caffeine leaves the system**: ~14 hours

## Caffeine Calculator

Beverage Type | Quantity | Caffeine Content | Body Weight | Total Intake | Caffeine per kg | Time to Metabolize |
---|---|---|---|---|---|---|

Coffee | 2 cups | 190 mg | 70 kg | 190 mg | 2.71 mg/kg | ~10 hours |

Energy Drink | 1 can | 80 mg | 60 kg | 80 mg | 1.33 mg/kg | ~5 hours |

Green Tea | 3 cups | 75 mg | 80 kg | 75 mg | 0.94 mg/kg | ~4 hours |

Espresso | 2 shots | 126 mg | 65 kg | 126 mg | 1.94 mg/kg | ~7 hours |

Cola | 2 cans | 70 mg | 75 kg | 70 mg | 0.93 mg/kg | ~4 hours |

Black Tea | 3 cups | 90 mg | 70 kg | 90 mg | 1.29 mg/kg | ~6 hours |

Iced Coffee | 16 oz | 200 mg | 80 kg | 200 mg | 2.50 mg/kg | ~10 hours |

Matcha | 1 serving (1 tsp) | 70 mg | 70 kg | 70 mg | 1.00 mg/kg | ~6 hours |

Dark Chocolate | 100 g | 50 mg | 75 kg | 50 mg | 0.67 mg/kg | ~4 hours |

Caffeinated Snack Bar | 1 bar | 100 mg | 70 kg | 100 mg | 1.43 mg/kg | ~5 hours |

Yerba Mate | 1 cup | 85 mg | 75 kg | 85 mg | 1.13 mg/kg | ~6 hours |

Caffeine Pill | – | Varies (200-300 mg) | – | – | – | – |

## Caffeine Overdose Calculation Formula

The formula for calculating potential caffeine overdose risk is:

**Caffeine Dosage (mg/kg) = Total Caffeine Consumed (mg) / Body Weight (kg)**

A dosage exceeding **15 mg/kg** is considered potentially dangerous.

A person weighing **60 kg** who consumes:

- 3 cups of coffee (300 mg)
- 2 energy drinks (160 mg)
- 1 caffeine pill (200 mg)

**Total caffeine intake**: 660 mg

**Caffeine Dosage = 660 mg / 60 kg = 11 mg/kg**

While this dosage is high, it’s below the **15 mg/kg threshold**.

## Recommended Caffeine Intake

Age Group | Recommended Daily Limit | Caffeine per kg (mg) | Example Body Weight (kg) | Total Caffeine Limit (mg) |
---|---|---|---|---|

Adults | Up to 400 mg | 2.5 – 4 | 70 | 175 – 280 |

Pregnant women | 200 mg or less | 1.5 – 3 | 70 | 105 – 210 |

Adolescents (12-18) | < 100 mg | 1.5 – 2.5 | 60 | 90 – 150 |

Children (< 12) | Not recommended | < 2.5 | 30 | < 75 |

Athletes | Up to 600 mg | 3 – 9 | 80 | 240 – 720 |

Individuals with Sensitivity | < 200 mg | < 3 | 50 | < 150 |

## How do you calculate how much caffeine you can have?

To determine your personal **caffeine limit**, consider the following steps:

**Establish a baseline**: Start with the recommended limit of **400 mg for adults**.

**Adjust for body weight**: A general rule is **3-6 mg per kg of body weight**.

**Consider individual factors**: Tolerance, sensitivity, and health conditions play a role.

For a healthy adult weighing **75 kg**:

- Baseline limit: 400 mg
- Weight-based calculation: 75 kg * 5 mg/kg = 375 mg

In this case, staying close to **375 mg daily** would be a reasonable limit.

**How much is 200 mg of caffeine?**

To put **200 mg of caffeine** into perspective:

- 2 cups (8 oz each) of brewed coffee
- 2.5 shots of espresso
- 5-6 cups of green or black tea
- 2 cans (16 oz each) of most energy drinks
- 5-6 cans (12 oz each) of cola

## How much caffeine will be left in his bloodstream after 4 hours, after 8 hours, and after 12 hours?

Let’s say someone consumes **300 mg of caffeine at 8:00 AM.**

- After 4 hours (12:00 PM): ~225 mg remaining
- After 8 hours (4:00 PM): ~150 mg remaining
- After 12 hours (8:00 PM): ~75 mg remaining

Caffeine has a **half-life** of approximately **5-6 hours** in healthy adults.

## Is 700mg of caffeine a lot?

Consuming **700 mg of caffeine in a day** is considered very high and exceeds recommended limits for most adults.

- 7 cups of coffee
- 8-9 energy drinks
- 17-20 cans of cola

Such high intake can lead to:

- Increased anxiety and restlessness
- Rapid heart rate
- Insomnia
- Digestive issues
- Potential caffeine toxicity

## How much caffeine in irn bru?

**Irn Bru**, a popular Scottish carbonated soft drink, contains approximately **32 mg of caffeine per 330 ml can**.

- Coffee (8 oz): 95-200 mg
- Cola (12 oz): 30-40 mg
- Energy drinks (8.4 oz): 70-80 mg

For someone consuming Irn Bru as their primary caffeine source, they would need to drink about **12 cans to reach the 400 mg daily limit**, which is unlikely for most individuals.

## Sources

- National Center for Biotechnology Information: Caffeine
- FDA: Spilling the Beans: How Much Caffeine is Too Much?
- Mayo Clinic: Caffeine: How much is too much?

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