Tom, a long PDF
Caffeine in the cup 80, Bedtime 23:00
With caffeine in the cup 80, bedtime 23:00, the calculator shows a planning figure. Illustration only, not advice.
Caffeine Focus Window
See a last-caffeine time that leaves room to sleep after a focus cup.
Your details
Fill the boxes, then calculate.
What is this calculator?
See a last-caffeine time that leaves room to sleep after a focus cup.
How it works
- Enter the figures you know.
- We apply a published or common planning method.
- Read the limitations under the result.
Common questions
What is the caffeine focus window?
Pair a caffeine dose with a last-cup time before bed. Use it as a guide, not a diagnosis.
Does this replace my GP?
No. Calculators stay in the browser and cannot see you.
Can I share the number?
Share fitness and fun results if you like. Keep lab and alcohol impairment numbers private.
Example scenarios
Rohan, focus before school pickup
Caffeine in the cup 97.6, Bedtime 23:00
With caffeine in the cup 97.6, bedtime 23:00, the calculator shows a planning figure. Illustration only, not advice.
Soraya, revision week
Caffeine in the cup 62.4, Bedtime 23:00
With caffeine in the cup 62.4, bedtime 23:00, the calculator shows a planning figure. Illustration only, not advice.
Understanding your results
Treat this as a snapshot for caffeine focus window, not a verdict. If the number worries you, take it to your GP rather than stacking new rules on yourself.
About this result
Guidance only. Calculations run in your browser. Numbers are estimates, not a diagnosis.
How we calculate
Eight-hour buffer before bedtime, with a typical five-hour half-life note.
Sources
Method described on this page. We link NHS or GOV.UK guidance where it applies.
Limitations
- Illustration only.
- Not personal medical advice.
Spotted an error? Request a correction or read our editorial policy.