Time Converter
Convert between seconds, minutes, hours, days, weeks, months, and years.
Each step along the axis is ten times the one before — the time units span 18 orders of magnitude, so a straight scale would bunch almost all of them at one end.
Instant insight
Months and years are not fixed lengths
A month is anywhere from 28 to 31 days, and a year is 365 or 366. Conversions using an "average month" are approximations.
For contracts and deadlines, count in days — everyone agrees how long a day is.
Check the direction of the conversion
Going from nanosecond to microsecond, the number should get bigger if the new unit is smaller, and smaller if it is bigger.
If it moved the wrong way, the factor has been applied upside down — the most common conversion error there is.
Worked out in your browser — nothing is sent anywhere. Comparison figures are approximate.
Common conversions
Quick Reference — 1 unit = ? Microsecond (μs)
| Unit | Value |
|---|---|
| Nanosecond (ns) | 0.001 |
| Microsecond (μs) | 1 |
| Millisecond (ms) | 1000 |
| Second (s) | 1000000 |
| Minute (min) | 60000000 |
| Hour (h) | 3600000000 |
| Day (d) | 86400000000 |
| Week (wk) | 604800000000 |
Formula
Multiply by (from factor / to factor)
Everyday Uses
Project durations
Convert 90 minutes to hours for billing, or 45 days into weeks for a project plan — clean unit shifts, no mental math errors.
Science and computing
Milliseconds to seconds, seconds to hours — translate response times, half-lives, and experiment durations correctly.
Media lengths
A 148-minute film is 2 h 28 min; a 5,400-second video is 90 minutes — convert for schedules and editing timelines.
Life in other units
How many hours old is a newborn? How many minutes in a school year? Fun and useful conversions for curious minds.
Billing and timesheets
Convert hours and minutes into decimal hours, which is what payroll and invoicing systems expect.
Video and audio durations
Turn a runtime in seconds into hours and minutes when planning a playlist or a lesson.
Frequently Asked Questions
How many seconds are in a day, week, and year?
1 minute = 60 seconds. 1 hour = 3,600 seconds. 1 day = 86,400 seconds (24 × 60 × 60). 1 week = 604,800 seconds. 1 year = 31,536,000 seconds (365 days) or 31,557,600 seconds (Julian year, 365.25 days). 1 decade = 315,576,000 seconds. A fun milestone: 1 billion seconds ≈ 31.7 years — so if you are about 31–32 years old, you have lived approximately 1 billion seconds.
How many hours and days are in a year — including leap years?
A standard calendar year = 365 days = 8,760 hours = 525,600 minutes. A leap year (every 4 years, with exceptions) = 366 days = 8,784 hours. The astronomical/Julian year = 365.25 days = 8,766 hours (used to define the light-year). The tropical year (Earth orbit) = 365.2422 days. Gregorian calendar correction: years divisible by 100 are not leap years unless also divisible by 400 (so 2000 was a leap year; 1900 was not).
Why are there 60 seconds in a minute and 60 minutes in an hour?
The base-60 (sexagesimal) number system originated in ancient Sumer and Babylon (~3000–2000 BCE). They chose 60 because it is highly composite — divisible by 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, and 60 — making fractions much simpler. This system was inherited by the Greeks and Romans and eventually standardised globally for time and angular measurement. The 24-hour day traces back to Egyptian astronomy dividing daylight and nighttime each into 12 parts.
How do milliseconds, microseconds, and nanoseconds compare?
1 millisecond (ms) = 0.001 seconds = 10⁻³ s (a blink of an eye takes ~150–400 ms). 1 microsecond (µs) = 0.000001 s = 10⁻⁶ s (a camera flash lasts ~1 ms = 1,000 µs). 1 nanosecond (ns) = 10⁻⁹ s (light travels ~30 cm in 1 ns). 1 picosecond = 10⁻¹² s (ultrafast lasers). Modern CPUs run at 3–5 GHz — each clock cycle takes 0.2–0.3 nanoseconds. RAM latency is typically 15–20 ns; an SSD takes ~100 µs; a hard drive ~10 ms.
How do you convert between months, weeks, and days accurately?
Exact conversions: 1 week = 7 days. 1 year = 52 weeks + 1 day (or 2 days in a leap year). Calendar months vary: 28–31 days. "Average month" = 365.25 ÷ 12 = 30.44 days (used in this converter). 1 year = 12 months = 52.18 weeks = 365.25 days (Julian average). For payroll and finance, note that "monthly" ≠ "4 weekly" — 4-weekly pay gives 13 pay periods per year, monthly gives 12. Always clarify which definition of "month" is being used in contracts and subscriptions.