Time Unit Converter

Convert any duration between years, months, weeks, days, hours, minutes and seconds.

Supports 26 units from picoseconds to the age of the Universe, plus compound hrs:min:sec notation.

Updated August 15, 2026

CreatorFrank Zhao

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Introduction

The Time Unit Converter shows one duration in every common time unit at once. Type a value into any of the eight fields — Years, Months, Weeks, Days, Hours, Minutes, Seconds or Other time units — and every other field updates immediately, so you never work out the base-60, base-24 and base-365 arithmetic by hand.

All eight fields always hold the same duration, just written in a different unit:

Years, Months, Weeks, Days, Hours, Minutes and Seconds each take a plain number in that unit — for example $2.5$ hours.
Other time units covers the rest of the range — from picoseconds and nanoseconds up to milliseconds, plus oversized scales such as billion years and the age of the Universe — along with compound forms like $\mathrm{hrs{:}min{:}sec}$ , $\mathrm{yrs{:}mos{:}days}$ or $\mathrm{days{:}hrs{:}min}$ .

Anyone who schedules tasks, logs runtimes, plans projects, checks uptime figures, or needs a value in the unit their spreadsheet or next tool expects will get the answer faster here than reaching for a calculator. The conversion runs both ways, so you can correct any single field and the others follow.

How to use / quick start

1Type the duration you already have into the field for its unit — for example $2.5$ into Hours, or $500$ into Other time units (which starts in milliseconds).
2Read the converted values — every other field updates as you type, so you see the whole equivalent at a glance without pressing anything.
3For a value that mixes units, such as $2{:}30{:}00$ (two hours, thirty minutes), switch the Other time units field's unit menu to hrs / min / sec and type the three parts — or just enter $150$ in Minutes.
4Copy the value your spreadsheet, log or next calculation expects. Correct any single field later and the rest follow automatically.

Worked example — $2.5$ hours in minutes, seconds and milliseconds

Type $2.5$ into the Hours field. The calculator first converts to seconds, then back out into every other unit:

2.5 \times 3600

=

9{,}000\ \mathrm{s}

9{,}000 \div 60

=

150\ \mathrm{min}

9{,}000 \times 1000

=

9{,}000{,}000\ \mathrm{ms}

So $2.5$ hours reads back as $150$ minutes, $9{,}000$ seconds, and $9{,}000{,}000$ milliseconds. Switch the Other field to hrs / min / sec and the same duration also appears as $2{:}30{:}00$ — the half hour becomes the minutes part.

The reverse works the same way: enter $150$ in Minutes and the Hours field fills in with $2.5$ . Whichever field you start from, the others follow.

Calculation method

Everything flows through seconds. Each unit has an exact number of seconds, and any duration is first converted to seconds, then re-expressed in the unit you're reading. If a value in one unit has $f$ seconds per unit and you want the same value in another unit with $f_{\mathrm{target}}$ seconds per unit:

A_{\mathrm{target}}

=

A_{\mathrm{source}} \times \frac{f_{\mathrm{source}}}{f_{\mathrm{target}}}

Seconds per unit

Unit	Seconds	Also equal to
1 picosecond	$10^{-12}\ \mathrm{s}$	—
1 nanosecond	$10^{-9}\ \mathrm{s}$	—
1 microsecond	$10^{-6}\ \mathrm{s}$	—
1 millisecond	$10^{-3}\ \mathrm{s}$	$\tfrac{1}{1000}\ \mathrm{s}$
1 second	1 s	—
1 minute	60 s	$\tfrac{1}{60}\ \mathrm{hr}$
1 hour	3,600 s	60 min
1 day	86,400 s	24 h
1 week	604,800 s	7 days
1 month	2,629,800 s	30.4375 days
1 year	31,557,600 s	365.25 days

Why a year is 365.25 days and a month 30.4375 days

This calculator uses one fixed average: a year is $365.25$ days, and a month is exactly a twelfth of that:

365.25 \div 12

=

30.4375\ \mathrm{days}

The $365.25$ figure is the average that sits between a $365$ -day common year and a $366$ -day leap year, so conversions that span years and months stay consistent no matter which calendar dates are involved. It is a duration convention, not a particular calendar year — real calendar months still run from $28$ to $31$ days.

Compound units carry for you

Because $60\,\mathrm{s} = 1\,\mathrm{min}$ , $60\,\mathrm{min} = 1\,\mathrm{hr}$ , $24\,\mathrm{h} = 1\,\mathrm{day}$ , $7\,\mathrm{days} = 1\,\mathrm{wk}$ and $12\,\mathrm{mos} = 1\,\mathrm{yr}$ , compound units normalize any overflow. Enter $5{:}75{:}30$ and it reads back as $6{:}15{:}30$ . Decimal values work too — $2.7$ hours is $2{:}42{:}00$ , because the $0.7$ hour is $42$ minutes.

Real-world examples

How long is 1,000,000 seconds?

Monitoring logs, video libraries and uptime reports often quote huge raw second counts. Say a server reports $1{,}000{,}000$ seconds of uptime. Type that into the Seconds field — the Days field fills in with $11.5740741$ :

1{,}000{,}000 \div 86{,}400

=

11.5740741\ \mathrm{days}

If a whole-day figure is more useful, switch the Other field to hrs / min / sec and the same uptime reads as $277{:}46{:}40$ — that is, $277$ hours, $46$ minutes and $40$ seconds, or about $11.6$ days.

A 500 ms time budget in software

Performance budgets are often quoted in milliseconds. If a request must finish in $500$ milliseconds but your profiling tool reports seconds, type $500$ into the Other field (which starts in ms) — the Seconds field shows the budget in seconds:

500 \div 1000

=

0.5\ \mathrm{s}

The Minutes field fills in with $0.00833333$ , so you can quote the same budget in whatever unit the tool or report expects.

Tips & best practices

A “month” here is 30.4375 days

Months are a twelfth of the fixed 365.25-day year, not a calendar window. If you need an exact date-to-date span, read it in days or weeks instead, where every day is exact.

Pick the unit that fits the size

A $90$ -minute task reads more naturally as $1.5$ hours than as $5{,}400$ seconds. For long stretches switch to days or weeks; for tiny intervals use the sub-second units in the Other field.

Use compound units to keep whole parts readable

$7{,}500$ seconds is a lot to read; switch the Other field to hrs / min / sec and it becomes $2{:}05{:}00$ . The $\mathrm{yrs{:}mos{:}days}$ and $\mathrm{days{:}hrs{:}min}$ forms do the same for larger spans.

Comma-grouped values paste cleanly

You can type or paste $1{,}000{,}000$ with the commas and it parses as one million seconds — no need to strip separators first.

Frequently asked questions

Does converting 2 months give me 61 days?

Not exactly — it gives $60.875$ days. Because a month here is a fixed $30.4375$ -day share of the 365.25-day year, two months come out as $2 \times 30.4375 = 60.875$ days. That is a consistent average, not a calendar window: March plus April, for example, would be $61$ days. For a date-to-date span, use the days or weeks units, where every day is exact.

Can I use this to work with calendar dates, timestamps or time zones?

No — this converter changes how a duration is written, so it has no notion of a starting date, weekday or time zone. If your seconds count is a Unix timestamp (seconds since 1970), the Unix Time Converter turns it into a calendar date and time. To see the same instant across the world, use the Time Zones Converter.

Limitations

This calculator changes how a duration is written — it does not measure time or add accuracy beyond the numbers you type. Results are only as precise as the input.
Months and years use a fixed 365.25-day average. Real calendar months run $28$ – $31$ days and calendar years have $365$ or $366$ days, so these units are for consistent large-duration estimates, not exact calendar math.
Only non-negative durations are accepted, and calendar semantics — dates, weekdays, timestamps and time zones — are out of scope. For those, use the Unix Time Converter or Time Zones Converter.

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