Caffeine Intake Calculator

Overview

This caffeine intake calculator adds up your daily caffeine from coffee, energy drinks, tea, and more, then compares the total with the maximum daily intake recommended by Korea's Ministry of Food and Drug Safety (MFDS): 400mg for adults, 300mg during pregnancy, and 2.5mg per kg of body weight for children and adolescents. Built-in presets cover common drinks — a tall americano at about 150mg, an instant coffee mix stick at about 50mg, a 250mL energy drink at about 80mg — and you can enter the labeled caffeine value of any product directly. If you exceed the limit, the calculator shows a warning with the amount over.

Formula

Total caffeine (mg) = Σ (caffeine per serving × number of servings)

Maximum daily intake (MFDS, consistent with EFSA/FDA):
- Adults: 400mg
- Pregnancy: 300mg
- Children & adolescents: body weight (kg) × 2.5mg

Percent of limit = total ÷ limit × 100

Example: 1 tall americano (150mg) + 1 coffee mix stick (50mg) = 200mg → 50.0% of the 400mg adult limit

How to Use

1. 1Pick your group — adults and pregnancy use fixed limits, while children and teens enter body weight for a weight-based limit (2.5mg/kg).
2. 2Add each drink you had today and enter the number of servings; use 'Add drink' to combine several kinds.
3. 3For canned drinks with a labeled caffeine content, choose 'Custom' and enter the printed mg value for best accuracy.
4. 4Check the total, percent of your daily limit, and remaining allowance; if the warning appears, avoid further caffeine today.

Examples

Background

Korea's MFDS sets the maximum daily caffeine intake at 400mg for adults, 300mg for pregnant women, and 2.5mg per kg of body weight for children and adolescents — figures consistent with the European Food Safety Authority (EFSA) and the US FDA's 400mg adult guidance. Caffeine blocks adenosine receptors to keep you alert, but with a half-life of roughly 4–6 hours, an afternoon coffee can still disturb sleep at night. Excess intake can cause insomnia, palpitations, anxiety, and stomach upset, and because the youth limit is weight-based, one or two energy drinks can push an adolescent over it. In Korea, high-caffeine drinks (over 0.15mg/mL) must display total caffeine content on the label, so the printed value is the most accurate input.

Tips

• ✔The same 'americano' ranges from about 75mg to 250mg depending on the brand and shot count — use the labeled or published value when available.
• ✔High-caffeine drinks in Korea are labeled with total caffeine in mg; entering that printed value beats any preset.
• ✔With a 4–6 hour half-life, caffeine within about 6 hours of bedtime can measurably cut sleep quality.
• ✔Even under the limit, palpitations, tremors, or insomnia mean the dose is too high for you personally — cut back gradually.
• ✔Chocolate, cola, and some combination cold medicines also contain caffeine and quietly add to your daily total.

FAQ