# Sleep Calculator & Sleep Music — Full Documentation

> Free sleep calculator and ambient sleep music — all in one place. Calculate your ideal bedtime and wake-up time based on 90-minute sleep cycles, then fall asleep with curated soundscapes.

Website: https://asleepcalculator.app

## What Makes This Different

Most sleep calculator websites are single-page tools that compute a bedtime and stop there. Sleep Calculator & Sleep Music is a complete sleep wellness platform that combines:

1. **Sleep cycle calculator** — bedtime and wake-up time based on 90-minute cycles
2. **Ambient sleep music mixer** — four-track sound mixer with alarm, moon mode, and scene visuals
3. **Nap planner with timer** — 20/40/90-minute options with built-in countdown
4. **Caffeine metabolism tracker** — half-life visualization showing when to stop drinking coffee
5. **Guided breathing exercises** — 4-7-8, Box Breathing, and Calm Breathing with animated visual guide
6. **Sleep tracker** — analyze sleep quality with scoring, cycle counting, and stage estimation
7. **Kids sleep calculator** — age-specific recommendations for newborns through teens
8. **Women's sleep guide** — how menstrual cycles, pregnancy, and menopause affect sleep

All tools are free, run entirely in the browser (no data collection), and are designed to work together — calculate your schedule, play sounds, set an alarm, all without leaving the site.

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## Page-by-Page Documentation

### Homepage — Sleep Calculator
- **URL**: https://asleepcalculator.app/
- **Purpose**: Calculate ideal bedtime or wake-up time based on 90-minute sleep cycles

The homepage features an iOS-style scroll wheel time picker with two modes:
- **"I want to wake up at..."** — calculates what time to go to bed
- **"I want to go to bed at..."** — calculates what time to wake up

**How it works:**
- Human sleep cycles last approximately 90 minutes each
- The calculator factors in 15 minutes average time to fall asleep
- Results show 3-6 cycle options (4.5h to 9h of sleep)
- 5-6 cycles (7.5-9 hours) are recommended for adults
- Waking at the end of a complete cycle reduces grogginess (sleep inertia)

**Results pages:**
- Bedtime results: https://asleepcalculator.app/bedtime-results/?time=07:00&ampm=AM
- Wake-up results: https://asleepcalculator.app/wakeup-time-results/?time=11:00&ampm=PM

Each result card shows: cycle count, sleep duration, recommendation level (Recommended/Acceptable/Short Rest), and a direct link to play sleep sounds.

---

### Ambient Sleep Music
- **URL**: https://asleepcalculator.app/sleep-music/
- **Purpose**: Mix calming ambient sounds to create a personalized sleep atmosphere

**Features:**
- 4 simultaneous audio tracks with individual volume control: ocean waves, rainfall, white noise, piano
- 8 visual scene backgrounds (beach dusk, starry sea, rain leaves, etc.)
- Master volume slider
- Wake-up alarm with configurable time (from URL parameter or manual)
- Moon mode: dims screen for darkness while audio plays
- Session timer: 15/30/45/60 min or continuous
- Fullscreen mode
- HLS audio streaming via Cloudflare R2 CDN
- Screen Wake Lock API to prevent device sleep during playback

**URL parameters:**
- `?alarm=7:00` — pre-sets wake-up alarm time (used when navigating from calculator results)

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### Nap Calculator & Planner
- **URL**: https://asleepcalculator.app/nap-calculator/
- **Purpose**: Plan the perfect power nap with a built-in timer

**Three nap profiles:**

| Duration | Name | Benefit | Sleep Stages |
|----------|------|---------|--------------|
| 20 min | Power Nap | Boost alertness (+26%*) | Light sleep only — avoids deep sleep grogginess |
| 40 min | Cognitive Refresh | Memory consolidation, creative problem-solving | Enters slow-wave sleep |
| 90 min | Full Cycle | Complete physical recovery, REM included | Full sleep cycle — minimizes grogginess |

*Source: Rosekind et al., Journal of Sleep Research, 1995

**Timer features:**
- 5 minutes added for falling asleep
- Real-time countdown with wake-up time display
- Audio alarm when timer completes
- Fullscreen mode
- Keyboard accessible (Enter/Space to start, Escape to cancel)

**Pro tip included:** "Nappuccino" — drink coffee immediately before a 20-min nap; caffeine kicks in as you wake up. Links to caffeine calculator.

---

### Caffeine & Sleep Calculator
- **URL**: https://asleepcalculator.app/caffeine-sleep-calculator/
- **Purpose**: Track how caffeine metabolism affects sleep timing

**Drink options (caffeine content):**
| Drink | Caffeine |
|-------|----------|
| Espresso | 63 mg |
| Latte | 80 mg |
| Cortado | 40 mg |
| Black Tea | 30 mg |
| Energy Drink | 160 mg |
| Custom | User-defined mg |

**Calculation model:**
- Caffeine half-life: 5.7 hours (average adult)
- Formula: remaining_mg = initial_mg × (0.5 ^ (hours_elapsed / 5.7))
- Sleep threshold: ~15 mg caffeine remaining at bedtime
- Visual SVG chart shows metabolism decay curve over 24 hours

**Risk levels:**
- Low (green): caffeine will clear before bedtime
- Moderate (yellow): some caffeine may remain
- High (red): significant caffeine at bedtime — shows alternatives

**Sleep-friendly alternatives suggested:**
- Chamomile tea (0 mg caffeine)
- Warm milk (tryptophan)
- Valerian root tea (natural sedative)

---

### Guided Breathing Exercises
- **URL**: https://asleepcalculator.app/sleep-breathing-exercises/
- **Purpose**: Guided breathing techniques to help fall asleep faster

**Three techniques:**

| Technique | Pattern | Best For |
|-----------|---------|----------|
| 4-7-8 | Inhale 4s → Hold 7s → Exhale 8s | Falling asleep |
| Box Breathing | Inhale 4s → Hold 4s → Exhale 4s → Hold 4s | Calming anxiety |
| Calm Breathing | Inhale 5s → Hold 2s → Exhale 7s | Gentle relaxation |

**Features:**
- Animated breathing circle: expands on inhale, contracts on exhale, pulses on hold
- SVG progress ring showing session progress
- Session durations: 3, 5, or 10 minutes
- Audio tones for phase transitions (440Hz inhale, 330Hz exhale, 392Hz hold)
- Sound toggle, pause/resume, reset controls
- Keyboard shortcuts: Space (pause), R (reset)
- Rotating inspirational quotes
- Session completion overlay with stats (technique, duration, cycles completed)

---

### Sleep Science
- **URL**: https://asleepcalculator.app/sleep-science/
- **Purpose**: Educational content about sleep cycle architecture

**Topics covered:**
- The 90-minute sleep cycle model
- Four sleep stages explained:
  - N1 (Light Sleep): 1-5 min, easily awakened
  - N2 (True Sleep): 10-25 min, body temperature drops
  - N3 (Deep Sleep): 20-40 min, physical repair, growth hormone
  - REM: 10-60 min, dreaming, memory consolidation
- Why waking at cycle boundaries reduces grogginess
- Sleep architecture changes through the night (more deep sleep early, more REM later)
- Nap science with alertness curve visualization
- Research references and citations

---

### Sleep Needs by Age
- **URL**: https://asleepcalculator.app/sleep-needs-by-age/
- **Purpose**: Age-appropriate sleep recommendations

| Age Group | Age Range | Recommended Hours | Key Tip |
|-----------|-----------|-------------------|---------|
| Newborns | 0-3 months | 14-17 hours | Sleep patterns are irregular; prioritize rest whenever possible |
| Toddlers | 1-2 years | 11-14 hours | Consistent nap routine prevents over-tiredness |
| Children | 6-13 years | 9-11 hours | Keep electronics out of bedroom for natural melatonin |
| Teens | 14-17 years | 8-10 hours | Natural clock shifts later; don't fight night owl tendency |
| Adults | 18-64 years | 7-9 hours | Quality matters as much as quantity; monitor deep sleep |
| Seniors | 65+ years | 7-8 hours | Early morning sunlight regulates sleep-wake cycle |

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### Sleep Calculator for Kids
- **URL**: https://asleepcalculator.app/sleep-calculator-for-kids/
- **Purpose**: Age-specific sleep recommendations for children from newborns to teens

**Features:**
- 6 age group cards: Newborns (0-3mo), Infants (4-11mo), Toddlers (1-2y), Preschool (3-5y), School Age (6-13y), Teens (14-17y)
- Interactive detail panel: click an age group to see recommended hours, nap info, and age-specific tips
- Built-in bedtime calculator: slide to set wake-up time, see ideal bedtime for that age group
- Signs of sleep deprivation section (difficulty waking, mood changes, trouble focusing)
- Sleep tips section (consistent routine, screen limits, cool bedroom, exercise)
- 5 FAQ items covering common parent questions

**Sleep recommendations (AASM guidelines):**
| Age Group | Hours | Naps |
|-----------|-------|------|
| Newborns (0-3 mo) | 14-17h | Irregular, 2-5 naps |
| Infants (4-11 mo) | 12-15h | 2-3 per day |
| Toddlers (1-2 yr) | 11-14h | 1-2 per day |
| Preschool (3-5 yr) | 10-13h | 0-1 per day |
| School Age (6-13 yr) | 9-11h | None needed |
| Teens (14-17 yr) | 8-10h | None, may need catch-up |

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### Sleep Calculator for Women
- **URL**: https://asleepcalculator.app/sleep-calculator-for-women/
- **Purpose**: How hormonal changes across life stages affect women's sleep

**Three main topics:**
1. **Menstrual Cycle & Sleep** — Follicular phase (better sleep), Luteal phase (disrupted), During period (cramps/bloating)
2. **Pregnancy Sleep Guide** — First trimester (fatigue), Second (best sleep), Third (back pain, heartburn)
3. **Menopause & Sleep** — Perimenopause (hot flashes), Menopause (insomnia), Post-menopause (lighter sleep)

**Key statistics:**
- 40% of women report sleep issues
- 28-day hormone cycle length
- 2-3x insomnia risk during menopause
- 78% experience pregnancy sleep disruption

**Sleep tips for women:** cycle tracking, temperature management, exercise timing, caffeine awareness

**References:** National Sleep Foundation, Sleep Health Journal, ACOG

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### Sleep Tracker
- **URL**: https://asleepcalculator.app/sleep-tracker/
- **Purpose**: Analyze sleep quality by entering sleep and wake times

**Features:**
- Dual slider input: "I fell asleep at" + "I woke up at"
- Sleep score (0-100) with animated ring visualization
- Score ratings: Excellent (90+), Good (75+), Fair (50+), Poor (<50)
- Complete cycle count and total sleep duration
- Estimated sleep stages breakdown: Light (~50%), Deep (~20%), REM (~25%), Awake (~5%)
- Stacked bar chart visualization of sleep stages
- Dynamic improvement tips based on your specific results

**Scoring model:**
- Based on complete 90-minute cycles (5 cycles = 100 base score)
- Penalties for oversleeping (>6 cycles) and very short sleep (<4.5h)
- Bonus for near-complete extra cycles

---

### Bedtime Results
- **URL**: https://asleepcalculator.app/bedtime-results/?time=07:00&ampm=AM
- **Purpose**: Shows personalized bedtime recommendations after calculator submission

**URL parameters:**
- `time` — target wake-up time (HH:MM format)
- `ampm` — AM or PM

**Displays 4 options:**
- 6 cycles (9h 15m) — Recommended, full recovery
- 5 cycles (7h 45m) — Recommended, sweet spot for most adults
- 4 cycles (6h 15m) — Acceptable, may feel afternoon fatigue
- 3 cycles (4h 45m) — Short rest, emergency only

Each card links to sleep music with pre-set alarm time. Includes share button (copies URL), siesta guide section, and quick sleep tips.

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### Wake-Up Time Results
- **URL**: https://asleepcalculator.app/wakeup-time-results/?time=11:00&ampm=PM
- **Purpose**: Shows optimal wake-up times based on bedtime

**URL parameters:**
- `time` — planned bedtime (HH:MM format)
- `ampm` — AM or PM

Same 4-option layout as bedtime results but calculates forward (bedtime + fall asleep time + cycles). Includes "Why these times?" explanation section, pro sleep tip, and links to recalculate or plan a nap. Time-aware greeting changes based on current hour.

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## Technical Details

- **Framework**: Astro 5.x (static site generation)
- **Styling**: Tailwind CSS 3.4
- **Audio**: HLS streaming via hls.js, hosted on Cloudflare R2
- **APIs used**: Screen Wake Lock API, Fullscreen API, Web Audio API, Clipboard API
- **All calculations are client-side** — no user data is sent to any server
- **No tracking cookies** — only essential cookies for language/theme preferences
- **Accessibility**: WCAG-compliant with ARIA labels, keyboard navigation, skip links, prefers-reduced-motion support

## Legal

- [Privacy Policy](https://asleepcalculator.app/privacy/) — No personal data collected; all calculations run locally
- [Terms of Use](https://asleepcalculator.app/terms/) — Educational tool, not medical advice
- [Cookie Policy](https://asleepcalculator.app/cookies/) — Essential + functional cookies only, no advertising