How many hours of sleep do I need?

Most adults need 7 to 9 hours of sleep per night according to the National Sleep Foundation 2022 guidelines. The optimal target for most people is 7.5 hours, which equals 5 complete 90-minute sleep cycles.

What is the best bedtime for a 7am alarm?

If your alarm is at 7am, the best bedtimes are 11:30pm (7.5 hours, 5 cycles) or 10pm (9 hours, 6 cycles). These are cycle-aligned times that let you wake at the end of a 90-minute sleep cycle.

🏛️ Harvard Sleep Medicine aligned 📋 NSF 2022 guidelines 🔬 Peer-reviewed sources ✅ Reviewed April 2026

Legal

Privacy Policy

Last updated: 2026-04-15. This policy explains what data we collect, how we use it, and your rights.

Plain English summary: We collect minimal data. We never sell your data. Calculator inputs never leave your device. You can unsubscribe and delete your data at any time.

Who We Are

BedtimeSleepCalculator.com is a free online sleep science tool. Contact: hello@bedtimesleepcalculator.com

What Data We Collect

Data you provide directly

If you subscribe to our newsletter or contact us, we collect your email address and any information you include. This data is used only to respond to you and send the content you requested.

Calculator usage data

All calculations happen entirely in your browser. We do not collect or store the bedtimes or alarm times you enter. This data never leaves your device.

Analytics and cookies

We use Google Analytics to understand aggregate site usage. We use local storage to remember your theme preference (dark or light mode). Affiliate tracking cookies may be set by third-party platforms when you click product links.

How We Use Your Data

To operate and improve the website and calculator tools
To respond to your enquiries and support requests
To send newsletters you have subscribed to (unsubscribe in every email)
To analyse aggregate usage patterns and improve our content
To comply with legal obligations

We do not sell, rent, or share your personal data with third parties for marketing purposes.

Third-Party Services

Google Analytics (aggregate analytics); Mailchimp (newsletter distribution); Amazon Associates and affiliate platforms (purchase tracking via product links).

Your Rights

You have rights to access, correct, delete, or export your personal data. Email hello@bedtimesleepcalculator.com to exercise any right. We respond within 30 days.

Children

We do not knowingly collect data from children under 13. Contact us immediately if you believe this has occurred.

Changes

We may update this policy. Material changes will be announced on the website. Continued use after a policy update constitutes acceptance.