Do months always equal 30 days?

No—months vary by calendar. To keep results consistent, the converter uses an average month (about 30.44 days). If you need exact calendar dates, use a date difference tool.

What about leap years or leap seconds?

These affect calendars and timestamps. This tool converts units (e.g., hours to days) using stable averages and definitions, so your results stay consistent and easy to explain.

Can I reverse a conversion?

Yes. Use the swap button to flip “from” and “to” units instantly.

Yes. Click the copy button for any result, or paste a number directly into the input to get started faster.

Time Unit Converter

Time unit cheat sheet

This master table lets you compare every time unit at a glance. Each row begins with “1 [unit]” and shows its equivalent value in all the other units.

Equivalents for common time units
Convert From	Millenium	Century	Decade	Year	Month	Week	Day	Hour	Minute	Second	Millisecond	Microsecond	Nanosecond
1 millennium =	1millen	10c	100dec	1000yrs	12,000.246mos	52,178.571wks	365,250d	8,766,000hrs	525,960,000min	31,557,600,000s	31,557,600,000,000ms	31,557,600,000,000,000µs	31,557,600,000,000,000,000ns
1 century =	0.1millen	1c	10dec	100yrs	1,200mos	5,218wks	36,524d	876,582hrs	52,594,920min	3,155,695,200s	3,155,695,200,000ms	3,155,695,200,000,000µs	3,155,695,200,000,000,000ns
1 decade =	0.01millen	0.1c	1dec	10yrs	120mos	521.775wks	3,652d	87,658hrs	5,259,492min	315,569,520s	315,569,520,000ms	315,569,520,000,000µs	315,569,520,000,000,000ns
1 year =	0.001millen	0.01c	0.1dec	1yr	12mos	52.1775wks	365.2425d	8,766hrs	525,949min	31,556,952s	31,556,952,000ms	31,556,952,000,000µs	31,556,952,000,000,000ns
1 month =	0.0000833millen	0.000833c	0.008333dec	0.083333yrs	1mo	4.348125wks	30.436875d	730.485hrs	43,829min	2,629,746s	2,629,746,000ms	2,629,746,000,000µs	2,629,746,000,000,000ns
1 week =	0.0000192millen	0.000192c	0.001917dec	0.019165yrs	0.229984mos	1wk	7d	168hrs	10,080min	604,800s	604,800,000ms	604,800,000,000µs	604,800,000,000,000ns
1 day =	0.0000027379millen	0.000027379c	0.000274dec	0.002738yrs	0.032855mos	0.142857wks	1d	24hrs	1,440min	86,400s	86,400,000ms	86,400,000,000µs	86,400,000,000,000ns
1 hour =	0.00000011408millen	0.0000011408c	0.000011408dec	0.000114yrs	0.001369mos	0.005952wks	0.041667d	1hr	60min	3,600s	3,600,000ms	3,600,000,000µs	3,600,000,000,000ns
1 minute =	0.0000000019013millen	0.000000019013c	0.00000019013dec	0.0000019013yrs	0.000022816mos	0.000099206wks	0.000694d	0.016667hrs	1min	60s	60,000ms	60,000,000µs	60,000,000,000ns
1 second =	0.000000000001millen	0.00000000031689c	0.0000000031689dec	0.000000031689yrs	0.00000038026mos	0.0000016534wks	0.000011574d	0.000278hrs	0.016667min	1s	1,000ms	1,000,000µs	1,000,000,000ns
1 millisecond =	0.000000000000001millen	0.00000000000031689c	0.0000000000031689dec	0.000000000031689yrs	0.00000000038026mos	0.0000000016534wks	0.000000011574d	0.00000027778hrs	0.000016667min	0.001s	1ms	1,000µs	1,000,000ns
1 microsecond =	0.000000000000031689millen	0.00000000000031689c	0.0000000000031689dec	0.000000000031689yrs	0.00000000038026mos	0.0000000016534wks	0.000000011574d	0.00000027778hrs	0.000016667min	0.000001s	0.001ms	1µs	1,000ns
1 nanosecond =	0.000000000000000031689millen	0.0000000000000031689c	0.000000000000031689dec	0.00000000000031689yrs	0.0000000000038026mos	0.000000000016534wks	0.00000000011574d	0.0000000027778hrs	0.000000016667min	0.000000001s	0.000001ms	0.001µs	1ns

Note: Month and year rows use long-term averages (≈30.44 days per month, ≈365.25 days per year). For exact calendar differences, use a date calculator.

Unit cheat sheet →

About the time unit converter

When you work with time-based data—whether you’re analysing logs, planning projects, or just satisfying your curiosity—converting between different time units can be frustrating. Our free Time Unit Converter makes it effortless to jump from milliseconds to centuries in a single click.

Why use a time converter?

Time comes in many scales. A developer might need to turn milliseconds into seconds to read API latency, while a historian might be thinking in decades or millennia. Doing these calculations by hand is slow and error-prone. With this converter you simply enter a value, pick the starting and target units, and get the result instantly.

Need to focus?

Did you know that the same reliable Time Unit Converter is also available in a minimalist version designed for deep focus and maximum productivity?

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You can also jump to quick conversions

Seconds → Minutes Minutes → Seconds Minutes → Hours Hours → Minutes Hours → Days Days → Hours Days → Weeks Weeks → Days Months → Years Years → Months

How the conversion works?

1. Normalise to seconds: the entered value is first multiplied by the exact number of seconds in the chosen source unit.

Example: 5 minutes × 60 = 300 seconds

2. Convert to the target unit: the seconds are then divided by the seconds per target unit.

Example: 300 seconds ÷ 3 600 = 0.0833 hours

This simple two-step formula guarantees precise results without rounding surprises.

Handy features

Swap units instantly: click the double-arrow button to flip your “from” and “to” units.
Clipboard shortcuts: paste numbers straight in, or copy the converted value out, with a single click.
Mobile-friendly design: inputs are right-aligned and touch-friendly so calculations are just as smooth on your phone.

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Practical uses

Developers: convert milliseconds or microservice response times to seconds or minutes.
Students & teachers: explain time conversions in physics or astronomy.
Event planners: quickly check how many hours or days fit between two dates.
Historians & writers: put centuries and millennia into perspective for your readers.

Updated on November 24, 2025 by Noah Morris Noah's avatar