Free website tool

Embed the caffeine calculator

Add a compact, evidence-conscious caffeine half-life calculator to an article or resource page. It starts empty, requires no account and clearly labels its result as an estimate.

Copy the embed code

<iframe src="https://caffcalc.app/embed" title="Caffeine at bedtime calculator" loading="lazy" style="width:100%;max-width:680px;height:660px;border:0;border-radius:18px" referrerpolicy="strict-origin-when-cross-origin"></iframe>

What the embed does

• Calculates exponential caffeine decay from one entered serving.
• Lets the visitor set intake time, bedtime and half-life.
• Runs inside the CaffCalc frame without sending calculation data to the host page.
• Includes CaffCalc attribution and an educational-use limitation.

Responsive height

The default fixed height works without JavaScript. Hosts that want automatic height adjustment can listen for a caffcalc:resize message from https://caffcalc.app and update the iframe height after validating the message origin.

Do not remove the attribution or present the estimate as medical advice. See the calculation methodology and editorial policy.