How much caffeine are you actually having?

Caffeine is the most widely used stimulant in the country, and the amount that is reasonable for you depends heavily on where you are at. The limit in pregnancy is half the adult one. Trying to conceive changes the picture again, and not in the way most people assume. This free tool, built by our Accredited Practising Dietitians, adds up a typical day from coffee, tea, soft drink, energy drinks, chocolate and supplements, and scores it against the figures from the Food Standards Australia New Zealand caffeine review approved in March 2026.

Check your caffeine intake

The limits are not one number

There is no single safe caffeine figure, which is why this tool asks where you are at first. For the general adult population, FSANZ concluded that moderate intake up to 400 mg a day is not associated with significant adverse effects. In pregnancy the figure is 200 mg a day, and Australian Government advice applies the same 200 mg while breastfeeding. For children and adolescents the limit is set per kilogram of body weight rather than as a flat number, 3.0 mg/kg for children and 5.7 mg/kg for adolescents, which is why the tool asks for a weight on those settings. A 25 kg child and a 70 kg teenager should not be measured against the same figure.

What too much caffeine actually does

Sleep, first and most often missed. Caffeine has a half-life of about four to six hours in a non-pregnant adult, so a 3pm coffee can still have a meaningful amount circulating at bedtime. People often fall asleep without trouble and still get lighter, less restorative sleep. If you are tired enough to need an afternoon coffee, the coffee may be part of the reason.

Anxiety, jitteriness and a faster heart rate. FSANZ notes that single doses above about 210 mg are associated with increases in blood pressure, plasma catecholamines and anxiety. If you already experience anxiety or panic, caffeine can amplify the physical symptoms, a racing heart or a tight chest, which can feed the cycle.

The tolerance loop. Regular intake builds tolerance, so the same cup does less over time. Stopping abruptly can bring on headache, fatigue, irritability and poor concentration, usually starting 12 to 24 hours after the last dose. Part of what a morning coffee fixes is withdrawal from yesterday’s. Reducing gradually over a week or two avoids most of that.

Iron absorption, the one people are most surprised by. Coffee and tea with a meal substantially reduce absorption of non-haem iron, the form found in plant foods, eggs and most supplements. In controlled studies a cup of coffee with a meal reduced iron absorption by about 39% and a cup of tea by about 64%. Iron from meat, chicken and fish is largely unaffected. If your iron is low you do not necessarily have to give either up, leaving about an hour between the meal and the drink recovers much of the difference. You can check your intake with our Iron Intake Calculator.

Using it instead of eating. Caffeine can blunt appetite and mask the fatigue that comes from not eating enough. If you find you are relying on it to get through the day in place of meals, that is worth a conversation rather than a rule. Get in touch and we can work through it properly.

Very high doses. Serious caffeine toxicity is rare from ordinary drinks but real from concentrated products such as powders, tablets and high-strength supplements. Australia has moved to prohibit the retail sale of pure and highly concentrated caffeine for this reason. Children are at higher risk because of their lower body weight, and FSANZ notes that infants and toddlers are over-represented in Australian and New Zealand poison centre calls. If you are worried about an exposure, the Poisons Information Centre is 13 11 26, 24 hours a day, anywhere in Australia.

Trying to conceive: his and hers are genuinely different

This is the part most caffeine advice skips, and the evidence is not what most people expect.

For her: larger reviews have not found a clear link between a woman’s caffeine intake and how long it takes to conceive. The more consistent signal is a higher reported risk of miscarriage once pregnant, at around 300 mg a day and above. Because pregnancy often is not detected for several weeks, this tool applies the 200 mg pregnancy limit to the preconception stage rather than waiting for a positive test.

For him: male intake is routinely overlooked, yet in a preconception cohort it was men’s caffeine that was inversely associated with the couple’s chance of conceiving in a given cycle, with a fecundability ratio of roughly 0.72 at 300 mg a day or more compared with under 100 mg, and around 0.47 above 700 mg. Findings on semen quality are mixed and not conclusive, and caffeinated soft drinks may carry other factors such as added sugar. It is a reason to moderate rather than a reason to be alarmed, and it is a reason for both partners to look at this, not just her.

A single large serve is its own question

Daily totals are not the whole story. FSANZ also notes that single doses above about 210 mg can raise blood pressure, plasma catecholamines and anxiety, separately from how much you have had across the day. That matters because a pre-workout scoop, an energy shot or a large filter coffee can clear that in one hit, while four cups of tea spread over a day will not. The tool flags this separately, so a day that looks fine on the total can still tell you a single serve is worth splitting.

Where it hides

Coffee is the obvious source, but it is rarely the whole picture. Energy drinks are regulated in Australia to contain between 145 and 320 mg per litre, so a 500 mL can can reach 160 mg on its own. Pre-workout powders vary enormously between brands and are frequently the single biggest contributor in a day. Guarana can carry up to 100 mg of caffeine per gram and appears in drinks and supplements where people do not look for it. Dark chocolate, chai, matcha and iced tea all add up quietly. The tool breaks your total down by source so you can see where it is actually coming from rather than guessing.

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