Caffeine Calculator: Tracking and Managing Your Caffeine Intake Overdose

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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