Last updated: September 24, 2026
What this checklist can and cannot tell you
Caffeine clearance varies several-fold between healthy adults, but there is no home test for it. The best available substitute is observation: how long a dose seems to stay with you, and how much of it you can still feel later in the day. This checklist collects exactly that kind of signal and turns it into a suggested preset for the calculator.
It cannot tell you your enzyme activity, it cannot account for prescription medication, and it is not a diagnosis. Treat the result as a starting point for the calculator's preset selector, not as a fact about your body. Nothing here is medical advice.
The self-check
Tick every statement that matches your experience over the last few months. The first group is about how quickly caffeine appears to leave your system; the second is about how strongly you feel it, which is a different question entirely.
Group 1: how long caffeine seems to last
Group 2: how strongly you feel it
Tick the statements that match you to see a suggested preset.
Nothing is scored until you choose at least one statement. Your answers stay in this browser tab and are never sent anywhere.
How the two groups are read
The first group is scored in two directions. Statements that point to a slower clearance build a slow score; statements that point to a faster one build a fast score. A clear gap between them suggests which preset fits you best. If the two sides come out close, the honest answer is the average preset, because your own day is not being limited by metabolism speed.
The second group is not added into that comparison. Feeling a small dose strongly, or feeling jittery from one cup, describes sensitivity rather than clearance. People often treat the two as the same thing, which leads to a specific confusion worth pulling apart.
Sensitivity and clearance are not the same thing
Clearance is a liver question: how quickly the caffeine is broken down and what is left in your bloodstream at a given hour. Sensitivity is a response question: how strongly your body reacts to whatever is present. Someone can clear caffeine quickly and still feel a single cup intensely, and someone can clear it slowly while noticing very little.
This matters for decisions. If your issue is sensitivity, the useful levers are dose size and how regularly you drink coffee. If your issue is clearance, the levers are timing and total daily load, because a smaller evening dose can still sit in your system for many hours. The metabolism overview covers what is actually being cleared and at what rate.
Confirming the guess with numbers
Whichever preset the checklist suggests, verify it against your own day rather than trusting the label. Add today's actual drinks and your real bedtime, then switch between fast, average, and slow. The spread between the three results tells you how much the answer depends on your metabolism:
- A wide spread. Your clearance assumption is doing real work in the decision, so the preset choice deserves the extra thought the checklist is asking you to give it.
- A narrow spread. Metabolism speed is not your bottleneck. A fixed habit, such as finishing coffee by early afternoon, is the more reliable fix.
Two companion pages make the comparison concrete: the dose by hour chart shows the same dose under all three presets, and the factors guide explains which influences are inherited, which are situational, and which are not worth worrying about.
Common questions
Is there a test that measures caffeine metabolism?
There is no routine clinical test for this, and no home test that measures it. Caffeine clearance can be estimated in research settings, but for everyday purposes the useful information is how your own intake seems to affect your sleep and how long you feel it, which is what this checklist asks about.
Does feeling jittery mean I am a slow metabolizer?
Not necessarily. Feeling a dose strongly is sensitivity, which is about how your body responds at the receptor level, while metabolism is about how quickly the liver clears caffeine. The two travel together often enough to be confusing, but they are separate: a fast metabolizer can still feel a morning coffee strongly, and a slow metabolizer may feel little from a large one.
Can I use this checklist as medical information?
No. It is an observational self-check built from everyday timing signals, not a diagnosis. If you have a health condition, take prescription medication, or are pregnant, the useful next step is a question to a pharmacist or doctor rather than a checklist.
My answers are mixed. What should I do?
Mixed answers are common and usually mean the average preset is the best starting point. Run your own day through the calculator with all three presets; if the numbers stay close together, your metabolism speed is not the deciding factor and the simpler advice is to watch the dose and the hour.
Related reading
- Caffeine Half-Life: How Long Caffeine Stays in Your System
- Caffeine Metabolism: How Your Body Clears Caffeine
- Caffeine Content Chart for Common Drinks
- Caffeine Cutoff Time: When Should You Stop Drinking Coffee?
- Coffee Before Bed: How Late Is Too Late to Drink Coffee?
- What Changes Caffeine Half-Life?
- How Much Caffeine Is Left? Dose by Hour Chart
- How Much Caffeine Is Left at Bedtime?
Run your own numbers
The CaffCutoff calculator turns these ideas into an estimate for your own day: add each drink, set a target bedtime, and read the remaining caffeine, the cutoff estimate, and the decay timeline.