Contact
Caffeine Curfew is one person — Toni Ristola, who built the calculator and wrote every explainer on it. Email is the only channel, and it reaches them directly.
A wrong number is worth reporting
The most useful thing you can send is a correction. Every caffeine figure in the drink table names the record it came from, and four of them are openly marked as estimates rather than measurements — if you have a better source for any of them, particularly a manufacturer's own published figure, that is worth more to this site than any amount of traffic. Say which drink and where the number comes from and it will be checked against what is there.
The same goes for the model itself. The half-life default, the 50 mg threshold and the ninety-minute cycle are all population averages doing a job they are only approximately suited to, and they are stated in the open precisely so someone who knows the literature better can say so.
Using the calculator elsewhere
The calculator embeds as a single iframe, carries no ads or analytics inside the frame, and is free to put on your own site — the credit line under it is the only thing asked in return. The calculator page has the snippet. Write if you want a size or a starting state it does not currently offer, or if you are translating it into a language the site does not yet cover.
What email cannot do
Nothing here is medical advice and no one answering this address is a clinician — not a doctor, not a sleep scientist, not a pharmacologist. Questions about your own sleep, your medication, caffeine in pregnancy or a racing heart cannot be answered here, and answering them would be worse than not replying. Those belong with someone who has information about you that this site never will.
For what the site does with your data, the privacy and cookies pages set it out in full; a privacy request can go to the same address.
Last updated 2026-09-01.