Time Converter

Free Online Time Converter

This time converter instantly converts between milliseconds (ms), seconds (s), minutes (min), hours (hr), days, weeks, months, years, and decades. It works as a seconds to minutes converter, minutes to hours converter, hours to days converter, days to weeks converter, and years to days converter all in one tool, so you never need to memorize individual conversion formulas or search for a separate calculator for every unit pair.

Whether you're a student solving math or physics homework involving elapsed time, a project manager converting task durations from hours to days, a developer converting milliseconds to seconds for a timer or API timeout, a fitness enthusiast tracking workout duration, or anyone planning a schedule that mixes minutes, hours, and days, this time conversion calculator gives you an instant, accurate result along with a visual diagram and complete step-by-step working so the math is never a mystery.

How to Use This Time Conversion Calculator

Using this online time converter takes only three quick steps. Enter the numeric value you want to convert, choose the unit you're converting from in the "From" dropdown, and choose the unit you want to convert to in the "To" dropdown — the converted result updates instantly as you type. Use the swap button to instantly reverse the conversion direction, or tap one of the popular conversion shortcuts like hours to minutes, days to hours, or weeks to days.

• Type the time value you want to convert
• Select the unit you're converting from (milliseconds, seconds, minutes, hours, days, weeks, months, years, or decades)
• Select the unit you want to convert to
• Read the converted time, the unit rate, and the visual conversion diagram

Time Conversion Formula

Every time conversion uses the second as a common base unit, since the second is the SI (International System of Units) standard for time. To convert any value from one unit to another, the calculator first multiplies the input by that unit's seconds factor to get the duration in seconds, then divides by the target unit's seconds factor to reach the final answer. This two-step method solves any equation you enter — just type a value and both units, and it computes automatically.

• Step 1: Time in seconds = Input value × (seconds factor of the "From" unit)
• Step 2: Result = Time in seconds ÷ (seconds factor of the "To" unit)
• Combined formula: Result = Input value × (From unit's seconds factor ÷ To unit's seconds factor)
• Example shortcut: to convert hours directly to minutes, multiply by 60

Common Time Conversion Factors

These are the exact seconds-based conversion factors this calculator uses internally. Knowing them is useful for quick mental estimates even when you don't have the calculator open:

• 1 millisecond (ms) = 0.001 seconds
• 1 second (s) = 1 second (the base unit)
• 1 minute (min) = 60 seconds
• 1 hour (hr) = 3,600 seconds = 60 minutes
• 1 day = 86,400 seconds = 24 hours
• 1 week = 604,800 seconds = 7 days
• 1 month (average) = 2,629,800 seconds ≈ 30.44 days
• 1 year (average) = 31,557,600 seconds ≈ 365.25 days
• 1 decade = 315,576,000 seconds = 10 years

Worked Example: Hours to Minutes

Suppose you want to convert a 2.5-hour meeting into minutes. First, look up the conversion factor: 1 hour equals 3,600 seconds, and 1 minute equals 60 seconds. Converting via seconds, 2.5 hr × 3,600 = 9,000 seconds, then 9,000 s ÷ 60 = 150 minutes. So 2.5 hours equals exactly 150 minutes — exactly what the diagram above shows when you enter 2.5 in the "From: Hour" field and select "To: Minute".

Now try a reverse example: converting 10,000 seconds of video playback into hours. Since 1 second equals 1 second exactly, you simply divide: 10,000 s ÷ 3,600 = 2.7778 hours. This two-step "convert to the base unit, then convert out" method is exactly what powers every conversion this calculator performs, no matter which two time units you enter into the equation.

Small, Common, and Large Time Units

Small time units like milliseconds and seconds are used in physics, computing, sports timing, and anywhere precise, short intervals matter — a website timeout, a sprinter's finish time, or an animation frame duration. Common time units like minutes, hours, days, and weeks are what most people use every day for scheduling, cooking, travel, and work.

Large time units like months, years, and decades are used for finance, planning, age calculation, and historical or demographic data. Because months and years don't divide evenly into days (a month can be 28 to 31 days, and a year has 365 or 366 days), this calculator uses standard average values — 30.44 days per month and 365.25 days per year — so long-range conversions like years to days or months to weeks stay consistent and accurate.

Where Time Conversion Is Used

Time conversion comes up constantly outside the classroom, in situations where durations from different scales need to be compared or combined:

• School and work, converting meeting or class durations between minutes and hours
• Software development, converting milliseconds to seconds for timers, timeouts, and performance benchmarks
• Project management, converting task estimates between hours, days, and weeks
• Finance and loans, converting repayment terms between months, years, and decades
• Fitness and sports, tracking workout, race, or rest interval durations
• Travel planning, converting flight or layover durations between hours and minutes