Convert time between milliseconds, seconds, minutes, hours, days, weeks and years — with exact factors.
What Is a Time Converter?
A time converter moves between time units: 90 minutes = 1.5 hours = 5,400 seconds. The second is the SI base unit (defined by atomic clocks); minutes, hours and days are the familiar sexagesimal system inherited from Babylon; the year here uses 365.25 days to average leap years. Payroll, billing and science all need these conversions — “1.5 hours” is how time-tracking software stores “1 h 30 m”.
How to Use
- Enter the value.
- Pick the “from” unit.
- Pick the “to” unit.
- Click “Convert Time”.
Formula
Convert to seconds first (value × from-factor), then divide by the to-factor.
Worked Example
90 minutes → hours: 90 × 60 ÷ 3,600 = 1.5 h. And 1 day → seconds: 86,400 s.
How It Works, In Plain Words
Every unit is stored as its length in seconds: a millisecond is 0.001, a minute is 60, an hour is 3,600, a day is 86,400, a week is 604,800 and a year is 31,557,600. Converting always passes through seconds — multiply by the from-factor, then divide by the to-factor — which is exactly the worked example’s route: 90 minutes times 60 makes 5,400 seconds, and 5,400 divided by the hour’s 3,600 gives 1.5 hours. Passing through one shared unit means every pair of units agrees with every other pair, with no separate table to keep in step.
The year’s factor shows the one deliberate approximation on the page. A year is entered as 365.25 days — three 365-day years and one 366-day year averaged, as the FAQs explain — so its 31,557,600 seconds already carries the leap-year correction. The small end matters just as much in the other direction: milliseconds exist for computing and science timings, where 0.001 of a second is the unit on the dropdown. Results show up to four decimal places, so 1.5 hours displays exactly, while longer spans in years keep their precision instead of rounding to whole years.
Real-World Uses
A freelancer billing by the hour converts a 90-minute call into 1.5 hours, because the invoicing software — like the payroll systems the introduction mentions — stores “1 h 30 m” as “1.5 hours”. A runner checking a finish recorded in seconds turns it into minutes and hours to compare against a target pace. A project planner with a span counted in days switches to weeks to report it the way the team plans, or into the 365.25-day years the converter uses when the span runs long. A developer timing a slow process drops to milliseconds, where the answer lives in thousandths of a second rather than in clock units. Each job is the same two hops through seconds, just entered from a different end of the scale.
Benefits
- Seven units from milliseconds to years
- The 365.25-day year averages leap years
- Decimal hours for payroll and billing
- Both directions in one tool
Features of Our Tool
- Instant results in your browser
- No sign-up, no download, 100% free
- Works on mobile, tablet and desktop
- Clear step-by-step explanation below the tool
- Private — your entries never leave your device
Common Mistakes
- Writing 1 h 30 m as 1.30 hours — it is 1.5
- Using 365 days for a year in long spans — the .25 matters over decades
- Confusing decimal minutes with seconds (0.5 h = 30 min, not 50)
Common Mistakes to Avoid
The classic error opens this page’s list: writing 1 h 30 m as 1.30 hours, when it is 1.5 — the digits after the point are sixtieths of an hour, not hundredths. The same trap catches decimal minutes: 0.5 h is 30 minutes, not 50, because the decimal part must be multiplied by 60, the method the last FAQ spells out with 1.75 h = 1 h 45 min. At the long end, using a flat 365 days for a year drops the leap-year quarter day, and the page warns the .25 matters over decades. And milliseconds invite their own slip: 0.001 is a thousandth of a second, so a result in ms is a thousand times the seconds figure, not a rounding of it.
FAQ
How many hours is 90 minutes?
1.5 hours.
How many seconds in a day?
86,400 seconds.
What is 1.5 hours in h m?
1 hour 30 minutes.
Why 365.25 days for a year?
To average the leap-year cycle: three 365-day years and one 366-day year.
How do I convert decimal hours to minutes?
Multiply the decimal part by 60: 1.75 h = 1 h 45 min.
How many minutes are in a week?
10,080 — a week is 604,800 seconds in this converter, and dividing by the minute’s 60 gives 10,080 minutes.
Why does the result show decimals instead of hours and minutes?
Because the tool converts into a single unit — 90 minutes becomes 1.5 hours. To read it as hours and minutes, multiply the decimal part by 60, as the FAQ above shows: 1.5 hours is 1 hour 30 minutes.