Duration Calculator

  • Meeting Time Across Time Zones Calculator
    Convert a meeting time from one city to another using UTC offsets. Instantly see the local time in City B and whether it falls on a different day.
  • Countdown to New Year Calculator
    Find out exactly how many days, hours, minutes and seconds remain until January 1 of next year from any chosen date and time.
  • Countdown to Date Calculator
    Countdown to any date and time. See the exact days, hours, minutes and seconds remaining — or how long ago a past date occurred.
  • Days Until Christmas Calculator
    Find out how many days until Christmas (December 25). Enter any start date for an instant countdown showing days and weeks until the holiday.
  • Work Hours Calculator with Lunch Break
    Calculate net work hours from clock-in and clock-out times after subtracting your lunch break. Supports overnight shifts. Free and instant.
  • Hours to Seconds Calculator
    Convert hours to seconds instantly. Enter any number of hours and get the exact equivalent in seconds using seconds = hours × 3600.
  • Intermittent Fasting Time Calculator
    Calculate when your fast ends and your eating window opens and closes based on your last meal and chosen fasting schedule like 16:8 or 18:6.
  • Half-Life Time Calculator
    Calculate the time required for a substance to decay from an initial quantity to a remaining amount using its half-life and the decay formula.
  • Time and a Half Calculator
    Calculate time and a half overtime pay. Enter your hourly rate, regular hours, and overtime hours to see your 1.5× overtime rate and total pay.
  • Days Ago Calculator
    Find out what date it was N days ago. Enter the number of days and get the exact past date, weekday, and ISO format instantly.
  • Weeks Between Dates Calculator
    Calculate the exact number of weeks and days between two dates. Enter a start and end date to get total weeks, remainder days, and decimal weeks.
  • Sleep Cycle Calculator
    Free sleep cycle calculator. Find the best bedtime or wake-up time based on 90-minute sleep cycles plus the time it takes you to fall asleep.
  • Rule of 72 Doubling Time Calculator
    Use the Rule of 72 to estimate how many years it takes an investment to double at a given annual rate. Fast, free doubling time calculator.
  • Years to Days Calculator
    Convert years to days instantly. Enter any number of years and get the equivalent days using the 365.25-day average year (accounts for leap years).
  • Add Months to a Date Calculator
    Add (or subtract) any number of months to a date. Handles month-end overflow by clamping the day to the last valid day of the resulting month.
  • Days Lived Calculator
    Find out exactly how many days you have lived. Enter your date of birth and an end date to count the total days, weeks, hours and years between them.
  • Shift Length Calculator
    Calculate how many hours you worked in a shift from start and end times minus your unpaid break. Handles overnight shifts that cross midnight.
  • Relationship Length Calculator
    Find out exactly how long you've been together. Enter your relationship start date to get years, months, days, total weeks and total days.
  • Calendar Days vs Business Days Calculator
    Count business days (workdays) between two dates. Subtracts weekends and optional public holidays from total calendar days. Free workday calculator.
  • 30 Days From Today Calculator
    Find out what date is 30 days from today (or any number of days). Get the exact future date and weekday instantly with this free date calculator.
  • Ovulation Date Calculator
    Estimate your ovulation day and fertile window from the first day of your last period and your average cycle length. Free, fast, and easy to use.
  • Years to Months Calculator
    Convert years into months instantly. Enter any number of years and this free calculator returns the equivalent number of months (years × 12).
  • Months From Today Calculator
    Find the exact date a set number of months from today (or before today). Add or subtract calendar months with automatic month-end day clamping.
  • Months to Days Calculator
    Convert months to days instantly. Uses the average month length of 30.4375 days for accurate, year-aware results. Free online months-to-days calculator.

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