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Caffeine Sleep Impact Calculator

Estimate how much caffeine remains active in your body at bedtime based on when you last consumed it and your personal sensitivity. Use it to decide your caffeine cutoff time so it doesn't wreck your sleep.

Caffeine Consumed (mg)

Time of Consumption (24h (e.g. 14.5))

Planned Bedtime (24h (e.g. 23))

Caffeine Sensitivity

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 Sleep Impact Calculator	Caffeine Sleep Impact Calculator
Category	Sleep	Sleep
Inputs required	4	3
Result	Caffeine in System at Bedtime (mg)	Caffeine Remaining at Bedtime (mg)
What it does	Estimate how much caffeine remains active in your body at bedtime based on when you last consumed it and your personal sensitivity. Use it to decide your caffeine cutoff time so it doesn't wreck 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.