Nutrition calculator
Caffeine Calculator
Total servings with the same caffeine strength, calculate daily mg/kg and compare the entered amount with selected reference figures.
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Add identical-strength caffeine servings
Use this form for servings that each contain the same caffeine amount. The total describes those servings only. It is a complete daily total only when every caffeine source that day has been accounted for.
Formulas and inputs
Total caffeine in mg = caffeine per serve × serves today. Daily mg/kg = that total ÷ body weight in kg. The mg/kg result describes the entered day's total relative to body weight; it is not a recommended workout dose.
- Enter body weight in kg and caffeine per complete serving in mg, using the product label or a credible estimate.
- Enter how many of those identical-strength servings were consumed. A half serve means half the entered serving amount.
- Select the adult or pregnant/breastfeeding daily reference. This changes the comparison amount, not the total.
- Read the daily and single-serving comparisons separately. Record any other caffeine sources before interpreting a full day's intake.
Worked caffeine examples
Two servings of one strength
At 70 kg, 120 mg per serving × 2 servings = 240 mg total. Dividing by 70 gives 3.4 mg/kg for the entered day. Each complete serving contains 120 mg.
Two identical drinks
Two drinks containing 160 mg each total 320 mg. Check the caffeine amount for the whole can or bottle, since a label may describe a smaller serving.
Different products need separate checks
A 150 mg coffee and a 250 mg pre-workout total 400 mg, but the largest individual serving is 250 mg. Calculate each product separately, then add daily totals manually. Entering the 200 mg average with two serves hides the 250 mg serving and produces a misleading single-serving message.
Caffeine entries that mislead
- Averaging different-strength products to fit the single-strength form.
- Entering a combined day's intake as one serving and then treating its single-serving comparison as meaningful.
- Confusing mg per 100 mL, mg per scoop and mg per complete serving.
- Omitting caffeine from tea, cola, tablets, gels or other products when adding the day's intake.
- Reading a reference comparison as proof that an amount is safe for you personally.
Intake arithmetic, with individual limits
The tool cannot assess individual caffeine sensitivity, interactions with medicines, cardiovascular conditions, pregnancy circumstances or sleep effects. Its reference selector does not perform a health assessment. Use appropriate professional advice when those factors affect your intake.
It does not calculate caffeine clearance, a half-life, bedtime effects or a recommended time to take caffeine. No time or elapsed-time field is used. The one-strength form also cannot assess a mixed-source day's highest serving by averaging doses.
What the reference messages mean
Food Standards Australia New Zealand's caffeine guidance lists an adult comparison of 400 mg per day from all sources and 200 mg in a single serving. It lists 200 mg per day from all sources for pregnancy and breastfeeding. This calculator is for adults; it does not apply the separate under-18 guidance.
The daily message is above the selected reference when the entered total exceeds it. The tool's close-to-reference message begins above 80% of that amount; this 80% band is a display rule, not a separate FSANZ health threshold. The single-serving message compares the entered full-serving strength with 200 mg. These are reference checks, not personal safety verdicts.
Totals are displayed in whole milligrams and daily mg/kg to one decimal. Label estimates and coffee preparation can introduce more uncertainty than the final rounding.
Check serving size before counting
If a label gives 80 mg per 250 mL and the bottle contains 500 mL, a full bottle supplies 160 mg. Enter 160 mg as the serving strength when one full bottle is your serving; do not multiply the serving count again for the same bottle.
For mixed products, keep a separate line for each product's strength, serving size and count. Sum the products for the day and check each full serving separately. This form does not store or combine that list for you.
Keep a caffeine intake record
Write down each product, caffeine per complete serving, amount consumed and any uncertainty in the label or estimate. Record the time separately if you are discussing sleep effects; the calculator does not use it.
The caffeine before workout guide and caffeine timing and sleep guide provide context beyond this intake calculation.
When a caffeine total needs professional advice
This calculator only adds the caffeine amounts entered. It does not assess pregnancy, breastfeeding, children, medication interactions, anxiety, heart rhythm problems, blood pressure, sleep disorders or individual sensitivity. Product labels and current health guidance take priority over a generic total.
Seek appropriate medical advice for concerning symptoms such as chest pain, fainting, severe palpitations or persistent sleep disruption. Do not use the calculator to justify an intake that causes symptoms.
Caffeine Calculator FAQs
Can I combine coffee and pre-workout in one entry?
Only when every entered serving has the same caffeine amount. For different strengths, calculate each product separately and add the daily totals manually. Do not enter an average: it can conceal a stronger individual serving.
What does the mg/kg result represent?
It is the total caffeine from the entered servings divided by body weight. It describes the entered day and is not a single workout dose or a personal recommendation.
Can it tell me when caffeine will leave my system?
No. There is no time, half-life, bedtime or remaining-caffeine calculation in this tool.
Does a result within the reference mean the intake is safe for me?
No. General reference comparisons do not account for sensitivity, conditions, medicines or symptoms. Use appropriate personal health guidance.
A reference result is not a target
A smaller total is not a reason to add caffeine until a reference is reached. The number does not assess tolerance, symptoms or whether any supplement is appropriate. Keep individual advice and product directions alongside the arithmetic.
Check the total and the strongest serving
For identical-strength servings, multiply mg per serve by serving count and check daily mg/kg. For different products, keep separate calculations and a manual daily sum so a stronger serving is not hidden by an average.