Morning Light Exposure Calculator
Lux targets by light source — how many minutes of which light actually sets your body clock.
The eye's clock cells (melanopsin) need *bright* light — indoor lighting is 100× dimmer than an overcast sky, which the eye's adaptation hides from you completely. Morning light anchors the rhythm earlier (better sleep onset that night), and the same physics is why evening screens delay it. Ten outdoor morning minutes is the cheapest sleep intervention in existence.
Formula
For general information only — not medical advice, a diagnosis or a treatment plan. Consult a qualified healthcare professional before making health, diet, medication or exercise decisions.
Lux targets by light source — how many minutes of which light actually sets your body clock. The Morning Light Exposure Calculator is a free, private morning light tool — every result computes instantly in your browser with no sign-up and no data upload.
About Morning Light Exposure Calculator
The eye's clock cells (melanopsin) need *bright* light — indoor lighting is 100× dimmer than an overcast sky, which the eye's adaptation hides from you completely. It applies circadian phase-setting scales with lux × duration in the ~1 h after waking. Use the Morning Light Exposure Calculator to get an instant, clearly-explained result with the working shown step by step — free, private and with the source method cited.
How to use Morning Light Exposure Calculator
- 1Enter your details in the Morning Light Exposure Calculator input fields above.
- 2The result updates instantly with the working and reference bands shown.
- 3Adjust any value to explore how it changes the outcome — it's free and unlimited.
Why use Morning Light Exposure Calculator?
- ✓Instant morning light result that recomputes as you type — no waiting, no page reloads
- ✓100% client-side: your health data never leaves your browser
- ✓Shows the actual formula and your numbers substituted in, so you can see exactly how the result is reached
- ✓Based on published, citable sources (Zeitzer JM et al., J Physiol 2000 — human light dose-response)
- ✓Free forever with no sign-up, account or app install
Frequently asked questions
How does the Morning Light Exposure Calculator work?+
The eye's clock cells (melanopsin) need *bright* light — indoor lighting is 100× dimmer than an overcast sky, which the eye's adaptation hides from you completely. The calculation uses the formula: circadian phase-setting scales with lux × duration in the ~1 h after waking. Everything runs instantly in your browser as you type — your inputs are never uploaded.
Is the Morning Light Exposure Calculator accurate, and what is it based on?+
The method is traceable to authoritative sources, including Zeitzer JM et al., J Physiol 2000 — human light dose-response; Lewy AJ — light and circadian phase research. Results are estimates — individual variation always applies, so treat the output as a well-grounded starting point.
Is the Morning Light Exposure Calculator free and private?+
Yes. It's completely free with no sign-up, and all computation happens locally in your browser, so none of your health data ever leaves your device.
Can I use this for medical decisions?+
This tool is for general information only and is not medical advice. Always consult a qualified healthcare professional before making health decisions.
What can I use the Morning Light Exposure Calculator for?+
It's commonly used for morning light, lux exposure, circadian light. Lux targets by light source — how many minutes of which light actually sets your body clock.
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