Caffeine Half Life Sleep Disruptor Calculator

📖 Overview

This calculator models caffeine decay from intake time to 11 PM and converts the remaining stimulant load into a sleep disruption estimate.

It helps users decide when to cut caffeine for better recovery.

Use these default and higher-pressure example inputs to explore how sensitive this calculator is before using your real numbers.

Estimates residual caffeine at 11 PM from dose timing and half-life, then converts that residual load into a sleep disruption score.

The Formula

Remaining mg at 11 PM = Dose × 0.5^((23 − DoseHour)/HalfLife)

Caffeine Dose	Total caffeine consumed in milligrams
Dose Hour	Consumption time on a 24-hour clock
Body Weight	Used for residual mg/kg context
Half-Life	Estimated caffeine half-life in hours
Sensitivity	Personal sleep sensitivity adjustment multiplier

💡This calculator is scenario-based. Better input quality leads to better decision quality.

⚠️This output is an estimate and not medical advice. Caffeine metabolism varies due genetics sleep debt medications and stress.

Dose @ 3 PM	Half-Life	Remaining at 11 PM	Typical Risk
200 mg	5 h	~66 mg	Moderate
300 mg	5 h	~99 mg	High
300 mg	7 h	~136 mg	Very high

Use this tool when you need a fast decision during active planning or execution.
Use this before committing money, time, or tradeoffs that are hard to reverse.
Use this to compare options using the same assumptions across scenarios.

Results can be misleading if key inputs are missing, stale, or unrealistic.
Very small or very large values may amplify rounding effects and interpretation risk.
If assumptions change mid-decision, recalculate before acting.

💡 If sleep quality matters keep late-day caffeine low and early.

💡 Use your own response history to tune half-life and sensitivity values.

💡 Track bedtime and wake quality to calibrate future caffeine cutoffs.

❓ Why does half-life matter so much?

Residual caffeine decays exponentially so slower metabolism leaves much more stimulant at night.

❓ What is a practical caffeine cutoff?

Many people perform better with no meaningful caffeine within 8 to 10 hours of bedtime.