How to read this chart
The chart below has three columns: the drink, its typical caffeine, and the time for that dose to fall under 50 mg at the average 5.5-hour half-life. The math is simple exponential decay: remaining = dose × ½(hours ÷ 5.5), solved for the moment the line dips under 50.
Two things to keep in mind before you trust any single number. First, 50 mg is a planning benchmark, not a medical “safe” line — it is the default bedtime target in our calculator because it is low enough that most people sleep through it, high enough to be practical. Second, “typical” means typical: a strong café brew can carry double the listed milligrams, and decaf varies by brand. When in doubt, use the number on your product’s label.
The chart
Drinks ordered from least to most caffeine:
“Already under” means the drink starts below the 50 mg benchmark — it still adds to your daily total, which is what the calculator tracks.
Why bigger drinks cost more than you think
Look at the jump from espresso to cold brew: roughly triple the caffeine, but the wait grows from 2 hours to 11. That is the quirk of half-life math — doubling the dose doesn’t double the wait, it adds roughly one half-life (about 5–6 hours) to reach the same leftover level.
Practically, this means a “just one” energy drink at lunch can outlast two morning coffees. People consistently underestimate big doses and overestimate small ones, which is exactly why eyeballing it fails and doing the math matters.
Your half-life moves every number
Every time in the chart assumes the 5.5-hour average. Real half-lives span roughly 2–12 hours between people, driven by genetics, age, pregnancy, smoking, and some medications.
- Fast metabolizers (caffeine barely touches you): your times run shorter than the chart — roughly halve them as a first guess.
- Slow metabolizers (one afternoon cup keeps you up): add around 50% to every time, and treat the chart as optimistic.
Don’t know which you are? Your own history is the best test: if a 3 PM coffee has ever cost you sleep, plan like you’re slow.
Put the chart to work
Translate it to a real evening. Bedtime 10:30 PM, target no more than ~50 mg left:
- Cold brew (~11 h to clear): last one by about 11:30 AM.
- Energy drink (~9 h): last one by about 1:15 PM.
- Brewed coffee (~5 h): last one by about 5:30 PM.
- Espresso (~2 h): last one by about 8:30 PM.
Find your exact cutoff. The free caffeine cutoff calculator runs this math for your bedtime, your actual doses, and your own half-life — no sign-up, everything in your browser.
Want the full hour-by-hour story for the biggest common dose? See how long 200 mg of caffeine lasts.
Frequently asked questions
How much caffeine is in a cup of coffee?▼
About 95 mg in a standard 8-oz cup of brewed coffee — but real cups vary widely. A strong café brew can top 150 mg, instant coffee runs around 90 mg, and a single espresso shot about 64 mg.
Which caffeinated drink wears off fastest?▼
Drinks that start under 50 mg — cola, green tea, black tea, decaf — are already below the benchmark. Among larger drinks, a single espresso (~64 mg) drops under 50 mg in about 2 hours at the average half-life.
Is 50 mg of caffeine at bedtime okay?▼
It is a planning benchmark, not a medical safety line. Many people sleep fine with a little caffeine on board; sensitive sleepers may want a lower target. The calculator lets you set your own.
Why does cold brew take 11 hours to clear?▼
Because 200 mg is four times 50 mg — that is two full half-lives (2 × 5.5 hours) to fall under the line. Each doubling of the dose adds roughly one half-life to the wait.