Time Unit Converter — Seconds, Minutes, Hours, Days, Weeks and More

Time units seem straightforward until you actually need to convert between them. How many seconds are in a year? How many weeks in a month? How long is a million seconds in days? These questions come up more often than you'd think — in project timelines, data science, video production, science problems, and just plain curiosity.

The CalcHub time converter handles every common time unit and a few you probably haven't thought about.

Time Unit Conversion Reference Table

From	To	Value
1 minute	seconds	60
1 hour	minutes	60
1 hour	seconds	3,600
1 day	hours	24
1 day	minutes	1,440
1 day	seconds	86,400
1 week	days	7
1 week	hours	168
1 week	seconds	604,800
1 year (365 days)	days	365
1 year	hours	8,760
1 year	minutes	525,600
1 year	seconds	31,536,000
1 decade	years	10
1 century	years	100

When You Actually Need a Time Converter

Project planning and billing — if you're estimating 40 hours of work and a client wants to know how many days that is (at 8 hours/day, it's 5 working days), or how many weeks (1 working week). This kind of conversion comes up constantly in freelancing and consulting. Video production — frame rates and timecodes use hours:minutes:seconds:frames. A 90-minute film at 24 fps is 90 × 60 × 24 = 129,600 frames. Converting between frame counts and wall clock time requires the right math. Science and data — timestamps in databases and programming are often stored as Unix timestamps (seconds since January 1, 1970). Converting 1,000,000,000 seconds to years gives about 31.7 years — so the Unix timestamp passed 1 billion seconds in September 2001. Speed distance time problems — if something travels at 60 mph for 90 minutes, you need to convert 90 minutes to 1.5 hours before the math works.

Tricky Time Conversions

Months are not uniform. A month can be 28, 29, 30, or 31 days. When converting "3 months" to days, you have to know which three months. The converter typically uses an average (30.44 days/month for a Gregorian year) — be aware of this when precision matters. Leap years. A calendar year is 365 days, but a sidereal year is 365.25 days (accounting for leap years). For most purposes, 365 days is fine. For astronomical calculations, use 365.25. Time zones don't affect duration conversions. 2 hours is 2 hours regardless of time zone. Time zones only matter when you're asking "what time will it be in Tokyo when it's 3 PM in New York?"

How to Use the CalcHub Time Converter

1. Go to calchub.in and open the Time Converter
2. Enter the number of time units you're working with
3. Select the source unit (e.g., "hours")
4. View the result in all other time units simultaneously

The all-at-once display is useful for quick sanity checks — like verifying that your "3-day deadline" is indeed 72 hours and 4,320 minutes.

Fun Time Facts Worth Knowing

Milestone	Duration
1 million seconds	~11.6 days
1 billion seconds	~31.7 years
Light travel time: Earth to Moon	~1.3 seconds
Light travel time: Earth to Sun	~8.3 minutes
Age of the universe	~13.8 billion years
Human lifespan (80 years)	~2.52 billion seconds

How many seconds are in a year?

Exactly 31,536,000 seconds in a standard 365-day year. In a leap year, it's 31,622,400. A rough rule of thumb: about 31.5 million seconds per year. This number comes up often in physics, astronomy, and programming.

What's the difference between a solar day and a sidereal day?

A solar day is 24 hours — the time it takes for the sun to return to the same position in the sky. A sidereal day is about 23 hours 56 minutes — the time it takes Earth to complete one rotation relative to distant stars. The difference exists because Earth also moves in its orbit around the sun while rotating.

How do you convert hours and minutes to just minutes?

Multiply the hours by 60 and add the remaining minutes. So 2 hours 45 minutes = (2 × 60) + 45 = 165 minutes. Going the other direction: divide minutes by 60; the quotient is hours, the remainder is minutes. 165 ÷ 60 = 2 hours remainder 45 minutes.

Related Converters

• Speed Converter — mph, km/h, m/s (requires time in consistent units)
• Energy Converter — kWh involves time as a factor
• Data Storage Converter — download time calculations