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Half-life calculator

This is the arithmetic behind Cafeity's Cycle View: a simple exponential decay from a published half-life. It describes a schedule model. It is not a measurement of anything in your body, and it cannot tell you anything about a dose.

Runs entirely in your browser. Nothing is sent anywhere, and nothing is stored.

How it is worked out

The formula

remaining = 0.5 ^ (days ÷ half-life). Three days after a dose with a five-day half-life leaves about 66% of that dose's contribution.

Published half-lives vary

Values differ by medication and are quoted as ranges, not constants. Enter the figure that applies to yours; the calculator does not choose one for you.

The hard limits

This is a schedule model, not a pharmacokinetic measurement. It cannot tell you whether a dose is working, whether to move one, or what to take. Those questions belong with a prescriber, and Cafeity will not answer them anywhere in the product.

Common questions

Is this the same as the Cycle View?
The same arithmetic. In the app it runs across your actual logged doses and overlays appetite, symptoms and intake, so you can see the rhythm of a week rather than a single number.
Can I use it to decide when to take a dose?
No, and Cafeity will never help with that. Dose timing is a decision for whoever prescribes it. This page exists to make the arithmetic transparent, not to advise.
Why does it say ‘sketch’?
Because a single-compartment decay curve ignores absorption, accumulation across repeated doses and individual variation. It is a useful shape, not a physiological claim.

This is general wellness information

Cafeity does not diagnose, treat or prevent any condition, and never recommends, calculates or adjusts a medication dose. Anything on this page is arithmetic you can check, not advice. Questions about your treatment belong with a licensed healthcare professional.

Other calculators

  • Protein calculator — A daily protein figure from body weight, using the same 1.4 g/kg derivation as the app.
  • Water intake calculator — A daily hydration figure from body weight, on the same 33 ml/kg basis as the app.
  • Fibre intake reference — The 25 g daily reference the app logs against, and how it is counted.
  • BMI calculator — Body mass index from height and weight, plus what it does and does not measure.

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