Time Converter

Convert between different time units from milliseconds to years

Time Converter

Common Time Conversions

1 second = 1,000 milliseconds
1 minute = 60 seconds
1 hour = 60 minutes
1 day = 24 hours
1 week = 7 days
1 year ≈ 365.25 days

Complete Time Unit Conversion Guide

Comprehensive guide to time measurements, conversions, and practical applications

Understanding Time Units

Standard Time Units

  • •Second (s): SI base unit of time
  • •Minute (min) = 60 seconds
  • •Hour (h) = 3,600 seconds
  • •Day = 86,400 seconds
  • •Week = 604,800 seconds
  • •Month ≈ 2,629,746 seconds (average)
  • •Year = 31,536,000 seconds (365 days) / 31,557,600 (Julian)

Scientific & Specialized Units

  • •Millisecond (ms) = 0.001 s
  • •Microsecond (μs) = 0.000001 s
  • •Nanosecond (ns) = 10⁻⁹ s
  • •Picosecond (ps) = 10⁻¹² s
  • •Fortnight = 14 days = 1,209,600 s
  • •Decade = 10 years
  • •Century = 100 years
  • •Unix time: seconds since Jan 1, 1970 UTC

Time Conversion Reference

Small to Large Units

  • •1 minute = 60 seconds
  • •1 hour = 60 minutes = 3,600 seconds
  • •1 day = 24 hours = 1,440 minutes = 86,400 seconds
  • •1 week = 7 days = 168 hours = 604,800 seconds
  • •1 month (avg) = 30.44 days = 730.5 hours
  • •1 year = 365 days = 8,760 hours = 525,600 minutes

Precision Time Units

  • •1 second = 1,000 ms
  • •1 ms = 1,000 μs
  • •1 μs = 1,000 ns
  • •1 ns = 1,000 ps
  • •Light travels 30 cm in 1 ns
  • •CPU at 3 GHz: 0.333 ns per cycle
  • •Human reaction time: ~200 ms
  • •Blink of an eye: 150–400 ms

Calendar Variations

  • •Leap year: 366 days = 31,622,400 s
  • •Gregorian year: 365.2425 days
  • •Julian year: 365.25 days
  • •Tropical year: 365.24219 days
  • •Sidereal day: 23 h 56 min 4.09 s
  • •Solar day: 24 h exactly
  • •UTC leap seconds added periodically

Professional Applications

Computing & Software

  • •Unix timestamp (seconds since epoch)
  • •Milliseconds for animation frame timing
  • •Nanoseconds for CPU profiling
  • •Database timestamps (datetime, epoch)
  • •API rate limiting (requests per minute/hour)
  • •Caching TTL (seconds)
  • •JWT token expiry (seconds)

Project Management

  • •Sprint duration (2 weeks)
  • •Deadline tracking (days/hours remaining)
  • •Billable hours (0.25 h = 15 min increments)
  • •Timesheet entries
  • •SLA response times (minutes)
  • •Uptime measurement (seconds of downtime)
  • •MTTR/MTBF in hours

Science & Engineering

  • •Radioactive half-life (milliseconds to billions of years)
  • •Signal propagation delay (nanoseconds)
  • •Chemical reaction rates (seconds to hours)
  • •Oscillation periods (nanoseconds to years)
  • •GPS timing accuracy (nanoseconds)
  • •Astronomical periods (days to millennia)

Healthcare & Medicine

  • •Drug half-life (hours to days)
  • •Patient vital sign intervals (seconds)
  • •Hospital stay duration (days)
  • •Medication frequency (hours between doses)
  • •Pregnancy duration (weeks)
  • •Clinical trial duration (months/years)
  • •Emergency response time (minutes)

Time Conversion Best Practices

Avoiding Common Errors

  • •Remember months vary in length (28–31 days)
  • •Leap year adds 1 day every 4 years
  • •Time zones affect wall clock time but not elapsed time
  • •Always specify UTC for international coordination
  • •Distinguish calendar months from 30-day months in contracts
  • •Unix epoch is in seconds; JavaScript uses milliseconds

Time Zone Awareness

  • •UTC is the global reference (no DST)
  • •POSIX time ignores leap seconds
  • •DST adds 1 hour in spring, removes in fall (US, EU)
  • •Some countries use half-hour or quarter-hour offsets (India UTC+5:30, Nepal UTC+5:45)
  • •International meetings: always specify time zone
  • •Use ISO 8601 for unambiguous timestamps

Time Conversion Examples

Everyday Conversions

  • •2.5 hours = 150 minutes = 9,000 seconds
  • •90 minutes = 1.5 hours
  • •1 week = 10,080 minutes
  • •45 days = 6 weeks 3 days = 1,080 hours
  • •1 year = 8,760 hours = 525,600 minutes
  • •1 decade = 3,652 days (includes 2–3 leap years)
  • •18 months = 1.5 years ≈ 547 days

Computing & Tech

  • •Unix timestamp 1,000,000,000 = Sept 9, 2001 01:46:40 UTC
  • •Unix timestamp 2,000,000,000 = May 18, 2033
  • •60 fps = 16.67 ms per frame
  • •30 fps = 33.33 ms per frame
  • •1 Gbps = 1 bit per nanosecond
  • •3 GHz CPU = 333 ps per clock cycle
  • •100 ms latency = 0.1 seconds

Science & Medicine

  • •Carbon-14 half-life: 5,730 years
  • •Uranium-238 half-life: 4.47 billion years
  • •Human heartbeat: 0.8 s at 75 BPM
  • •Light crosses Earth: 42 ms
  • •Sound crosses a room (10 m): 29 ms
  • •Typical drug half-life (ibuprofen): 2 hours
  • •Pregnancy: 40 weeks = 280 days

Frequently Asked Questions

How many seconds are in a year?▾
A standard year has 31,536,000 seconds (365 days × 24 hours × 60 minutes × 60 seconds). A leap year has 31,622,400 seconds (366 days). The Julian year used in astronomy has 31,557,600 seconds (365.25 days), while the Gregorian mean year has 31,556,952 seconds (365.2425 days).
What is a Unix timestamp?▾
A Unix timestamp is the number of seconds that have elapsed since 00:00:00 UTC on January 1, 1970 — known as the Unix epoch. It is the standard way computers store and compare dates and times across different time zones. Note that JavaScript's Date.now() returns milliseconds since epoch, not seconds, so you often need to divide by 1,000 when working between systems.
How do I convert hours to minutes and seconds?▾
To convert hours to minutes, multiply by 60. To convert hours to seconds, multiply by 3,600. For example, 2.75 hours × 60 = 165 minutes, and 2.75 hours × 3,600 = 9,900 seconds. For mixed results (e.g., 2 hours 45 minutes 0 seconds), take the whole number as hours, multiply the decimal by 60 for minutes, and repeat for remaining seconds.
What is the difference between a solar day and a sidereal day?▾
A solar day is exactly 24 hours — the time from one solar noon to the next. A sidereal day is 23 hours, 56 minutes, and 4.09 seconds — the time for Earth to complete one full rotation relative to distant stars. The ~4-minute difference exists because Earth also moves along its orbit while rotating, requiring a slight extra rotation to face the Sun again.
How are leap years calculated?▾
A year is a leap year if it is divisible by 4, except for century years (divisible by 100), which must also be divisible by 400. So 2000 and 2400 are leap years, but 1900 and 2100 are not. This rule keeps the Gregorian calendar aligned with Earth's orbit to within 26 seconds per year.
Why do months have different numbers of days?▾
Month lengths are a historical artifact from the Roman calendar and later reforms. The Gregorian calendar has 7 months with 31 days, 4 with 30 days, and February with 28 days (29 in a leap year). The irregular lengths exist because calendar makers tried to align months with seasons and lunar cycles while keeping the year close to 365.25 days.