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Caffeine Half-Life Sleep Impact Calculator

See exactly how much caffeine remains in your bloodstream at any point after consumption. Ideal for planning your last coffee of the day without ruining your sleep.

Caffeine Consumed (mg)

Hours Since Consumption (hours)

Body Weight (kg)

Metabolism Rate

Fill in the required fields to see your result.

Sleep

Caffeine Sleep Impact Calculator

Calculate how many milligrams of caffeine remain active in your system at bedtime based on when and how much you consumed, using a standard 5-hour half-life. Even moderate residual caffeine at bedtime measurably disrupts sleep architecture, not just sleep onset.

Caffeine Consumption Time (hours (24h format))

Caffeine Amount (mg)

Desired Bedtime (hours (24h format))

Fill in the required fields to see your result.

Key differences

	Caffeine Half-Life Sleep Impact Calculator	Caffeine Sleep Impact Calculator
Category	Sleep	Sleep
Inputs required	4	3
Result	Caffeine per kg Body Weight (mg/kg)	Caffeine Remaining at Bedtime (mg)
What it does	See exactly how much caffeine remains in your bloodstream at any point after consumption. Ideal for planning your last coffee of the day without ruining your sleep.	Calculate how many milligrams of caffeine remain active in your system at bedtime based on when and how much you consumed, using a standard 5-hour half-life. Even moderate residual caffeine at bedtime measurably disrupts sleep architecture, not just sleep onset.