Time Converter
Convert between seconds, minutes, hours, days, weeks, months, and years.
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.
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.