In your system at
bedtime
0mg
—
Peak level
0 mg
—
Sleep-safe from
—
—
Total intake
0 mg
—
Your drinks
Half-life5.7 h
Typical adult is 5–6 h. Smokers clear it in ~3 h; pregnancy or the pill can push it past 10 h.
Absorption rate3.10
Sleep threshold50 mg
The level you want to be under when you go to bed.
Wake
Bedtime
The chart starts at your wake time.
One-compartment model with first-order absorption, same as the workbook:
C(t) = Σ Dᵢ · kₐ/(kₐ−kₑ) · (e^−kₑ(t−tᵢ) − e^−kₐ(t−tᵢ)), with kₑ = ln2 / half-life.
It tracks caffeine in the body in mg, not blood concentration. Serving sizes are typical values and
real drinks vary a lot — it's a rough personal estimate, not medical advice.