Time Unit Converter

How to use this calculator

Three inputs. The result shows multiple equivalents at once.

Time value is the number you’re converting. Type it in the field. Decimals work. Very large and very small numbers work too, though the output may display in scientific notation for anything beyond a few orders of magnitude.

From unit is your source unit. The dropdown covers: Nanosecond (ns), Microsecond (µs), Millisecond (ms), Second (s), Minute (min), Hour (hr), Day, Week, Month, Year, Decade, Century.

To unit is your target. Same list.

Click Calculate and the blue results panel shows the converted value plus a breakdown across the most common units: seconds, minutes, hours, days, and years all displayed at once. Scientific notation (like 2.778e-4) appears for very small numbers; that’s 0.0002778, meaning 1 second is 0.0002778 hours.

The Duration Scale below the results uses a log-scale bar chart to show your input and output alongside each other. Because time spans 20+ orders of magnitude from nanoseconds to centuries, a log scale is the only way to meaningfully visualise the relative sizes.

What the duration scale shows

The Duration Scale section is a log-scale bar chart. This needs a brief explanation because log scales are unfamiliar to most people.

On a normal scale, 10 and 20 are the same distance apart as 1,000 and 1,010. On a log scale, each step represents a 10× increase. So the distance from 1 to 10 is the same as the distance from 1,000 to 10,000.

Time units span such extreme ranges that a normal scale is useless. If you drew seconds and years on a linear chart, years would be so far to the right that seconds would be invisible. The log scale compresses the enormous range so you can see where every unit sits relative to every other.

The bars for each unit (seconds, minutes, hours, days, years) show proportional length on this log scale. A full bar means the current input value. A tiny sliver means the converted value is tiny relative to the input. It’s a visual answer to “how much bigger is X than Y?”

The formulas

All conversions go through seconds as the base unit. Every unit has a fixed number of seconds, and the calculator converts by dividing through seconds.

The seconds-per-unit values:

Seconds to all time units: full conversion table

Seconds	Minutes	Hours	Days	Weeks	Years
1	0.0167	0.000278	0.0000116	0.00000165	3.17e-8
60	1	0.01667	0.000694	0.0000992	1.90e-6
600	10	0.1667	0.00694	0.000992	1.90e-5
3,600	60	1	0.04167	0.00595	0.000114
86,400	1,440	24	1	0.14286	0.002738
604,800	10,080	168	7	1	0.01916
2,629,800	43,830	730.5	30.44	4.348	0.08333
31,557,600	525,960	8,766	365.25	52.18	1
315,576,000	5,259,600	87,660	3,652.5	521.8	10
3,155,760,000	52,596,000	876,600	36,525	5,218	100

Hours, minutes and seconds: the everyday range

The conversions people reach for most often.

Hours	Minutes	Seconds	Days
0.25	15	900	0.01042
0.5	30	1,800	0.02083
1	60	3,600	0.04167
1.5	90	5,400	0.0625
2	120	7,200	0.08333
3	180	10,800	0.125
4	240	14,400	0.16667
6	360	21,600	0.25
8	480	28,800	0.33333
12	720	43,200	0.5
24	1,440	86,400	1
48	2,880	172,800	2
72	4,320	259,200	3
168	10,080	604,800	7

Days, weeks, months and years

Days	Weeks	Months (avg)	Years
1	0.1429	0.03285	0.002738
7	1	0.2299	0.01916
14	2	0.4598	0.03833
30	4.286	0.9856	0.08214
30.44	4.348	1	0.08333
60	8.571	1.971	0.16427
90	12.86	2.957	0.24641
180	25.71	5.914	0.49281
365.25	52.18	12	1
730.5	104.36	24	2
1,826	260.9	60	5
3,652.5	521.8	120	10
36,525	5,218	1,200	100

The small end: nanoseconds, microseconds, milliseconds

Used in computing, electronics, and physics. These numbers are counterintuitive because they’re so small.

Unit	Seconds	Nanoseconds	Microseconds	Milliseconds	Context
1 nanosecond	10⁻⁹	1	0.001	0.000001	One CPU clock cycle at 1 GHz
1 microsecond	10⁻⁶	1,000	1	0.001	WiFi packet timing, camera flash
1 millisecond	0.001	1,000,000	1,000	1	Audio sample at 1 kHz, blink duration
10 ms	0.01	10,000,000	10,000	10	Human reaction time (lower bound)
100 ms	0.1	100,000,000	100,000	100	Perceptible audio/video lag
250 ms	0.25	250,000,000	250,000	250	Average human reaction time
1 second	1	1,000,000,000	1,000,000	1,000	Heartbeat (60 BPM)

Time at scale: perspective on large numbers

Some durations people frequently need to convert or contextualise.

Duration	Seconds	What it means
1 minute	60
1 hour	3,600
1 day	86,400
1 week	604,800
1 month (avg)	2,629,800
1 year	31,557,600	~31.6 million seconds
4 years	126,230,400	US presidential term, Olympic cycle
10 years	315,576,000	~316 million seconds
18 years	568,036,800	Age of majority in most countries
75 years	2,366,820,000	Average human lifespan (developed world)
100 years	3,155,760,000	~3.16 billion seconds
1,000 years	31,557,600,000	A millennium
1 million years	3.156 × 10¹³	Geological epoch
Age of universe	~4.35 × 10¹⁷	~13.8 billion years

Real-world examples

Software timing: API timeout

A developer sets a network request timeout at 30,000 milliseconds. Is that reasonable?

Project management: sprint planning

A software team works in 2-week sprints. A project is estimated at 6 months. How many sprints is that?

Physics: speed of light across distances

Light travels at 299,792,458 m/s. How long does it take to travel from the Sun to Earth (~150 million km)?

Loan duration: mortgage in seconds

A 30-year mortgage. How many seconds is the borrower committed for?

Computing: billion operations per second

A processor runs at 3 GHz (3 billion cycles per second). How long does each cycle take?

Common mistakes people make

Assuming 1 month = 30 days exactly. Months are 28, 29, 30, or 31 days. The calculator uses 30.44 days (365.25 / 12) as an average. For anything involving actual calendar dates (lease expiration, subscription billing, contract terms), count the specific calendar days rather than using an average.

Mixing up milliseconds and microseconds. Millisecond (ms) = 1/1,000 of a second. Microsecond (µs) = 1/1,000,000 of a second. They’re 1,000× apart. In computing contexts, latency specs and timing requirements bounce between both. A 100 µs response time is 0.1 ms, which is very fast. A 100 ms response time is 100,000 µs, which is perceptible to a user.

Not accounting for leap years. A year isn’t exactly 365 days. The Gregorian calendar uses 365.2425 days per year on average (the calculator uses 365.25, which is close but not exact). Over long periods this matters: the difference between 365 and 365.25 is 1 day every 4 years, which compounds to 25 days per century.

Treating “business days” as regular days. 10 business days is not 10 days. It’s 14 calendar days (assuming a 5-day work week with no holidays). Project timelines and legal deadlines often specify business days. The calculator converts calendar time; business day calculations require separate logic.

Reading scientific notation wrong. The calculator output shows values like 3.169e-8 for very small numbers. This means 3.169 × 10⁻⁸ = 0.00000003169. The negative exponent tells you how many places to move the decimal point to the left. 1e-3 is 0.001. 1e-6 is 0.000001. Each step of 3 in the exponent is a 1,000× change.

How different fields think about time

Each discipline has a “natural” time unit that everything else is measured relative to.

Field	Primary time unit	Why
Computing / electronics	Nanoseconds, clock cycles	CPU speeds and signal timing
Audio engineering	Milliseconds, samples	Latency and sample rate (44,100/s)
Human perception	Milliseconds (10-500 ms)	Reaction time, perceptible lag
Sports timing	Milliseconds, hundredths	Race results and photo finishes
Everyday life	Minutes, hours	Scheduling and duration
Project management	Days, weeks, sprints	Planning and milestones
Finance and contracts	Days, months, years	Interest periods, terms
Biology / medicine	Seconds, minutes, years	Heart rate, drug half-life, age
Geology / evolution	Thousands to millions of years	Stratigraphic periods
Astronomy / cosmology	Light-years, billions of years	Cosmic distances and timescales

The bottom line

Time units span 26 orders of magnitude from nanoseconds to the age of the universe. No other measurement category covers that range in everyday use. The calculator handles all of it and shows multiple equivalents simultaneously so you’re not running conversions one at a time.

For everyday use (hours, minutes, seconds, days), the conversions are simple enough to do mentally with the table. For anything involving milliseconds, nanoseconds, or decades and centuries, just enter the value and read the result.

The one thing to remember: months are approximate. If a deadline or contract matters, count calendar days.