Estimate your optimal sleep and wake times based on your lifestyle.
Your Circadian Rhythm Insights:
Understanding Your Circadian Rhythm
Your circadian rhythm is your body's internal 24-hour clock that regulates a natural cycle of physical, mental, and behavioral changes. It's primarily influenced by light and darkness. A well-aligned circadian rhythm is crucial for overall health, impacting sleep quality, mood, energy levels, cognitive function, and metabolism.
This calculator helps you explore how your desired sleep and wake times, along with your target sleep duration, might align with your body's natural tendencies. While this tool provides an estimation, individual chronotypes (early birds vs. night owls) and external factors can influence your ideal schedule.
How the Calculator Works:
The calculator uses the following logic:
Sleep Window Calculation: It first determines the time difference between your desired wake-up time and your usual bedtime, considering if the wake-up time is on the next day.
Alignment Check: It then checks if the available time within this window (from bedtime to wake-up time) is sufficient to cover your desired sleep duration.
Optimal Sleep Duration Estimation: If the window is longer than your desired sleep duration, it suggests an optimal sleep duration centered within that window.
Optimal Wake/Sleep Time Suggestions: Based on your desired wake-up time and sleep duration, it provides a potential "ideal" bedtime and a "best" wake-up time that maximizes sleep quality within the established window.
Note: This calculator is a simplified model. For personalized advice, consult a healthcare professional or a sleep specialist.
Key Factors and Use Cases:
Consistency is Key: Going to bed and waking up around the same time every day, even on weekends, is vital for maintaining a stable circadian rhythm.
Light Exposure: Maximizing natural light exposure in the morning and minimizing artificial light (especially blue light) in the evening helps anchor your internal clock.
Lifestyle Adjustments: Use this calculator to see how shifting your schedule might impact your sleep. It can be helpful for planning travel across time zones, adjusting to new work shifts, or generally improving sleep hygiene.
Understanding Chronotypes: While this calculator doesn't directly measure your chronotype (e.g., lark or owl), it can help you see how your preferred times align with a typical 24-hour cycle.
function calculateCircadianRhythm() {
var bedtimeStr = document.getElementById("bedtime").value;
var wakeUpTimeStr = document.getElementById("wakeUpTime").value;
var sleepDuration = parseFloat(document.getElementById("sleepDuration").value);
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (isNaN(sleepDuration) || sleepDuration 10) {
resultDiv.innerHTML = "Please enter a valid desired sleep duration between 4 and 10 hours.";
return;
}
// Convert time strings to minutes from midnight
var bedtimeParts = bedtimeStr.split(':');
var bedtimeMinutes = parseInt(bedtimeParts[0]) * 60 + parseInt(bedtimeParts[1]);
var wakeUpTimeParts = wakeUpTimeStr.split(':');
var wakeUpTimeMinutes = parseInt(wakeUpTimeParts[0]) * 60 + parseInt(wakeUpTimeParts[1]);
// Calculate total minutes in a day
var minutesInDay = 24 * 60;
// Calculate the duration between bedtime and wake-up time
var sleepWindowMinutes;
if (wakeUpTimeMinutes >= bedtimeMinutes) {
// Wake up on the same day as bedtime (e.g., bedtime 23:00, wake up 07:00 next day)
sleepWindowMinutes = (minutesInDay – bedtimeMinutes) + wakeUpTimeMinutes;
} else {
// Wake up on the next day (e.g., bedtime 02:00, wake up 10:00 same day) – this case is less common for overnight sleep
// For typical overnight sleep, the previous case handles it. This else might represent unusual schedules.
// We'll assume typical overnight sleep where wake-up time is numerically later OR on the next day.
// If wakeUpTimeMinutes < bedtimeMinutes, it implies the wake up is on the *next* calendar day.
sleepWindowMinutes = (minutesInDay – bedtimeMinutes) + wakeUpTimeMinutes;
}
var sleepWindowHours = sleepWindowMinutes / 60;
var outputHtml = "";
outputHtml += "Usual Bedtime: " + formatTime(bedtimeMinutes) + "";
outputHtml += "Desired Wake-Up Time: " + formatTime(wakeUpTimeMinutes) + "";
outputHtml += "Desired Sleep Duration: " + sleepDuration + " hours";
outputHtml += "Available Sleep Window: Approximately " + sleepWindowHours.toFixed(2) + " hours.";
if (sleepWindowHours < sleepDuration) {
outputHtml += "Warning: Your desired sleep duration (" + sleepDuration + " hours) is longer than your available sleep window (" + sleepWindowHours.toFixed(2) + " hours) between your usual bedtime and desired wake-up time. You may not achieve your desired sleep duration.";
// Suggest a realistic sleep duration and calculate times based on that
var realisticSleepDuration = Math.min(sleepDuration, sleepWindowHours);
var idealBedtimeMinutes = wakeUpTimeMinutes – (realisticSleepDuration * 60);
if (idealBedtimeMinutes < 0) {
idealBedtimeMinutes += minutesInDay; // Adjust for crossing midnight
}
outputHtml += "To maximize rest within this window, consider a sleep duration of about " + realisticSleepDuration.toFixed(2) + " hours.";
outputHtml += "Estimated Ideal Bedtime: " + formatTime(idealBedtimeMinutes) + "";
outputHtml += "Best Wake-Up Time (to fit " + realisticSleepDuration.toFixed(2) + " hours): " + formatTime(wakeUpTimeMinutes) + "";
} else {
// Calculate optimal bedtime to get desired sleep duration ending at desired wake up time
var idealBedtimeMinutes = wakeUpTimeMinutes – (sleepDuration * 60);
if (idealBedtimeMinutes < 0) {
idealBedtimeMinutes += minutesInDay; // Adjust for crossing midnight
}
// Calculate midpoint of sleep window
var midpointBedtime = bedtimeMinutes;
var midpointWakeup = wakeUpTimeMinutes;
if (midpointWakeup < midpointBedtime) midpointWakeup += minutesInDay; // ensure correct diff
var midSleepWindow = midpointBedtime + (midpointWakeup – midpointBedtime) / 2;
var optimalMidpointBedtimeMinutes = midSleepWindow – (sleepDuration * 60) / 2;
if (optimalMidpointBedtimeMinutes < 0) optimalMidpointBedtimeMinutes += minutesInDay;
outputHtml += "Based on your desired wake-up time and sleep duration:";
outputHtml += "Recommended Bedtime: " + formatTime(idealBedtimeMinutes) + "";
outputHtml += "Best Wake-Up Time: " + formatTime(wakeUpTimeMinutes) + "";
outputHtml += "Midpoint of Sleep Window: " + formatTime(optimalMidpointBedtimeMinutes) + " (This can be a reference for when your body naturally feels most sleepy or alert)";
if (sleepWindowHours > sleepDuration + 1) { // If there's a generous buffer
outputHtml += "Your desired sleep schedule fits well within your available window, allowing for flexibility.";
}
}
resultDiv.innerHTML = outputHtml;
}
// Helper function to format minutes from midnight to HH:MM
function formatTime(totalMinutes) {
var hours = Math.floor(totalMinutes / 60);
var minutes = totalMinutes % 60;
hours = hours % 24; // Ensure hours wrap around 24
return String(hours).padStart(2, '0') + ":" + String(minutes).padStart(2, '0');
}