Contact SleepCalcs

SleepCalcs is run by a small independent publisher of free online tools. If you have a question or a problem, or you want to tell us something about the site, write to us by email.

Email: thefreecollection@gmail.com

What you can write to us about

Response time

We read every message. We usually reply within 5 business days. Bug reports and corrections may take a little longer if we need to check the tool before answering.

Please note

SleepCalcs tools give general estimates. We cannot give personal medical advice by email. If you have concerns about your sleep or your health, please speak to a qualified health professional.

Frequently Asked Questions

Yes. Every tool on SleepCalcs is free to use with no account required. We support the site through unobtrusive ads, never by selling data or pushing subscriptions.
Sleepyti.me was one of the original sleep calculators but became heavily ad-focused after being sold in 2019. SleepCalcs offers a broader toolkit (20 tools vs 1), cleaner design, and keeps ads minimal and non-intrusive.
No. Every tool works directly in your browser on any device. Nothing to install.
Our calculators use established sleep science (90-minute cycles, chronotype research, circadian principles). They provide general guidance, not medical advice. If you have a sleep disorder, please see a qualified healthcare provider.
Research shows human sleep cycles average 90 minutes, moving through light sleep, deep sleep, and REM. Waking at the end of a full cycle (rather than mid-cycle) generally feels less groggy. Our calculators time your wake-up to these cycle endings.
We use standard web analytics (Google Analytics) to understand site usage, but we do not store, sell, or share personal sleep data. All calculations happen in your browser.