24-Hour Caffeine Intake Calculator (mg per day)

What it does

The calculator documents the caffeine-containing products a patient used over a 24-hour period and estimates the total in milligrams. Enter the number of servings (in half-serving steps) for each source and the tool multiplies by the mg per serving, shows a subtotal per row, and sums the total. Caffeine intake is often worth quantifying when assessing anxiety, insomnia, or palpitations.

Sources and default values

The list includes brewed coffee in 8, 12, and 16 oz sizes, espresso, cold brew, instant and decaf coffee, black, green, and matcha tea, regular and diet cola, small and large energy drinks, energy shots, pre-workout powder, 100 mg and 200 mg caffeine tablets, and dark chocolate. A few of the defaults:

Source	Serving	Default mg
Brewed coffee	8 oz cup	95
Espresso	1 shot	64
Black tea	8 oz	47
Soft drink / cola	12 oz can	34
Energy drink	16 oz (large)	160
Energy shot	2 oz shot	200

Every mg-per-serving value can be edited to match a specific brand or brew strength, and a custom row covers any other source.

Interpreting the total

The tool flags the total against three ranges. Up to 400 mg/day is within the ceiling generally cited as safe for healthy adults (FDA). Above 400 mg/day, anxiety, insomnia, and palpitations are more likely. Above 600 mg/day is flagged as high intake, prompting review for caffeine use and toxicity risk. The commonly cited limit in pregnancy is under 200 mg/day.

What the report includes

The plain-text report lists the date, each source used with servings × mg per serving and the subtotal, and the estimated 24-hour total. It adds the 400 mg and 200 mg reference points and notes that doses approaching about 1,200 mg have been associated with toxic effects. All totals are estimates based on typical serving content, and actual caffeine varies by brand and preparation.