Blue Light Exposure Planner

Plan your daily light exposure to support your circadian rhythm. Calculate your optimal blue-light reduction window based on your target bedtime. For shift workers, travelers, and anyone using screens at night. All calculations run offline in your browser.

Educational only, not medical advice.

Plan Your Exposure

Target Bedtime

When you plan to fall asleep.

Reduction Window

Recommended: 2–3 hours for significant impact.

I am a shift worker / have unusual schedule

Your Blue Light Plan

Start reducing blue light by:

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That's -- before your target bedtime.

Interpretation

Enter your bedtime to see personalized guidance.

Evening Strategy

After start time, use night mode/blue light filters on devices
Prefer dim, warm-toned lighting
Consider blue-blocking glasses if using screens

Why Blue Light Timing Matters

Blue light, especially from screens and LED lights, suppresses melatonin production and can shift your circadian rhythm. Managing exposure in the evening helps signal to your body that it's time to wind down, potentially improving sleep onset and quality.

How to Use This Planner

Set your realistic target bedtime (when you aim to be asleep).
Choose a reduction window (2–3 hours is commonly studied).
Plan evening activities after the start time to minimize bright/blue light.
Use the strategy list for practical adjustments.

Example Scenarios

Bedtime 10:30 PM, 2‑hour window: Start reducing blue light at 8:30 PM. Dim lights, enable night mode.
Bedtime 11:45 PM, 3‑hour window: Begin at 8:45 PM. Consider blue‑blocking glasses if working late.
Shift worker (sleep 8 AM): Use blackout curtains and avoid blue light after 5 AM.

Typical Light Exposure Guidance

Time Before Bed	Light Recommendation	Melatonin Impact
4+ hours	Bright light OK, natural daylight best	Minimal suppression
2–3 hours	Reduce blue light; use warm, dim lights	Partial suppression if bright
1 hour	Minimize all screens; very dim lighting	High suppression risk

What‑If: Adjust Your Window

See how changing your reduction window affects your evening schedule.

Reduction Window: 2 hours --:--

0.5h 2.5h 5h

1 hour

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2 hours

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3 hours

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4 hours

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Frequently Asked Questions

How accurate is this planner?

It provides a general timing framework based on circadian science. Individual sensitivity varies—some people may need longer or shorter windows.

What if I must use screens late?

Use built‑in night modes (reduce color temperature), lower brightness, increase distance, and consider blue‑blocking glasses. Even partial reduction helps.

When should I seek help for sleep issues?

If you consistently have trouble falling/staying asleep, experience daytime fatigue, or suspect a sleep disorder, consult a healthcare provider or sleep specialist.

Does morning light matter?

Yes. Morning bright light (especially outdoors) helps anchor your circadian rhythm and can improve evening sleepiness.

Formulas & Assumptions

Calculation: Start time = Bedtime − Reduction window (in hours).
Times are calculated in 24‑hour format, respecting day boundaries (times after midnight adjust correctly).
Rounding: Results are shown to the nearest minute.
Assumption: Blue light reduction is most critical within 2–3 hours of bedtime for typical indoor lighting conditions.

For informational and educational purposes only. Estimates depend on your inputs and simplifying assumptions. This tool is not medical advice and does not diagnose or treat any condition. If you have symptoms, abnormal readings, or urgent concerns, contact a qualified healthcare professional.

Common unit conversions and measurement best practices

Typical wellness metric ranges and public health guidance concepts

Basic circadian rhythm and light exposure concepts

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Blue Light Exposure Planner

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