Duration Calculator

  • Hours, Minutes & Seconds Addition and Subtraction Calculator
    Add and subtract up to five time durations in hours, minutes and seconds, with a repeat multiplier. Get a normalized H:M:S total plus decimal hours, minutes and seconds.
  • Road Trip Time Calculator
    Estimate total road trip time from distance, average speed, and rest stops. Adds driving time plus break time for a realistic arrival estimate.
  • Year Progress Calculator
    Find out what percentage of the year has passed for any date. Calculates day of year, days remaining, and year progress percent for leap and non-leap years.
  • How Many Weeks Pregnant Am I?
    Find out how many weeks and days pregnant you are from your last menstrual period (LMP). Enter your LMP and an as-of date to get gestational age instantly.
  • Weeks From Today Calculator
    Find the exact date N weeks from today (or before today). Enter a number of weeks to get the target date, weekday, and total day offset instantly.
  • Milliseconds to Seconds Calculator
    Convert milliseconds to seconds instantly. Enter any value in ms and get the equivalent seconds using seconds = milliseconds ÷ 1000.
  • Layover / Connection Time Calculator
    Calculate your flight layover or connection time in minutes between arrival and next departure, and check if it beats the minimum connection time.
  • Pregnancy Weeks to Months Calculator
    Convert weeks pregnant to months instantly. Enter your gestational age in weeks to see how many months pregnant you are, using 4.34524 weeks per month.
  • Weeks and Days Between Two Dates Calculator
    Find the number of weeks and days between two dates. Great for pregnancy tracking, project timelines, and counting elapsed time fast and accurately.
  • Hours to Minutes Calculator
    Convert hours to minutes instantly. Enter any number of hours and get the exact equivalent in minutes using the formula minutes = hours × 60.
  • Seconds to HH:MM:SS Calculator
    Convert any number of seconds into hours, minutes, and seconds (HH:MM:SS) instantly. Free, accurate time conversion calculator.
  • Time Clock Calculator (Clock-In / Clock-Out)
    Free time clock calculator. Enter clock-in and clock-out times for each work period and get your Total Time in hours:minutes plus decimal hours.
  • Stopwatch Timer Calculator - Add & Subtract Lap Times
    Add or subtract stopwatch lap times in mm:ss.s like an adding machine. Keeps a running total that rolls into hours. Perfect for race splits and lap sums.
  • Day of the Week Calculator
    Find what day of the week any date falls on. Get the weekday name, day-of-year, days in the month and year, and which ordinal weekday it is.
  • Time Arithmetic Calculator
    Add, subtract, multiply, or divide spans of time in days, hours, minutes and seconds. Get a normalized result or a unitless time ratio instantly.
  • Date Difference Calculator
    Calculate the number of days or business days between two dates. Supports US, EU and ISO date formats, leap years, and optional Saturday counting.
  • Time Card Hours Calculator
    Free time card calculator: enter start and end times, deduct breaks, and get total hours worked as hh:mm, decimal hours, and minutes instantly.
  • Time Calculator hh:mm:ss (Add and Subtract Time)
    Adding-machine time calculator. Add and subtract hh:mm:ss values into a running total. Flexible separators (: . - space), negative times, zero-padded result.
  • Minutes to Hours Converter
    Convert minutes to hours instantly. Get hours-and-minutes, hh:mm clock format, and decimal hours from any number of minutes. Free, accurate, universal.
  • Minutes to Decimal Hours Converter
    Convert hours and minutes into decimal hours for time cards and payroll. Enter hours and minutes, choose decimals, and get hours in decimal form instantly.
  • Training Pace Calculator
    Turn a recent race time into easy, tempo, threshold and long-run training paces. Free running pace calculator showing seconds per km for each zone.
  • Running Split Calculator
    Calculate your per-split time and total finish time from your target running pace and distance. Plan even splits for races and training runs.
  • Weekday Count in Date Range Calculator
    Count how many Mondays through Sundays fall between two dates (inclusive), plus total days. Free weekday counter for shift planning and working-day counts.
  • Race Time Predictor Calculator
    Predict your race finish time at any distance using Riegel's formula. Enter a known time and distance to forecast 5K, 10K, half & full marathon times.

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