Page updated October 5, 2026

Legal

Terms of Service

Effective from: October 5, 2026

These terms govern your use of Lull, available at instacalc.co ("we," "us," or "the site"). By using this site, you agree to these terms. If you don't agree, please don't use the site.

What this site is

Lull provides eight sleep timing calculators (bedtimes and wake-up times, sleep need by age, night-shift sleep, naps, jet lag, caffeine cut-off, sleep debt and social jet lag), a methodology and sources page listing every value they use, and a changelog. The calculators run in your browser and turn published guidance into estimated clock times and amounts; see our About page for how they are built.

Not medical advice

Nothing on this site is medical advice, and no content here should be used to diagnose, treat, cure, or prevent any condition. The calculators give simplified estimates based on population averages and a few labelled rules of our own; they do not account for your individual health, medical history, medicines, or sleep disorders. The tool pages cite public sources such as the CDC, NIOSH, NIH, the NHS and the FDA for general information, but they are not a substitute for professional medical care. If you have ongoing sleep problems or health concerns, talk to a qualified healthcare provider.

Use at your own discretion

You're responsible for how you use the information and suggestions on this site. We make no guarantee that following a suggested bedtime, wake-up time, nap, caffeine cut-off or travel plan will produce any particular result, and individual sleep needs and patterns vary.

No warranty

This site and its content are provided "as is," without warranties of any kind, express or implied, including accuracy, completeness, or fitness for a particular purpose. We aim to keep the calculators' arithmetic and their sources accurate and up to date, but we don't guarantee it is without errors at all times.

Limitation of liability

To the extent permitted by law, we aren't liable for any damages arising from your use of, or inability to use, this site or its content.

Third-party links and advertising

The tool and methodology pages link to external sources, including government health sites, for reference. We aren't responsible for the content or practices of those external sites. This site also displays advertising served by Google AdSense; see our Privacy Policy for details on how that works and what data is involved.

Intellectual property

The text, design, and calculator logic on this site are our own work unless otherwise noted, and are provided for personal, non-commercial use. Don't reproduce or redistribute substantial portions of the site's content without permission.

Governing law

These terms are governed by the laws of Serbia. Operated by Quiet Hours Studio (Serbia).

Changes to these terms

We may update these terms from time to time. Changes will be posted on this page with a new “Effective from” date. Continued use of the site after a change means you accept the updated terms.

Contact

Questions about these terms can be sent to support@instacalc.co, or see our Contact page.