Time Converter — Convert Hours, Minutes, Seconds, and Time Zones

How to Use the Time Converter

1. Open the time converter.
2. Select unit conversion to convert between time units (seconds, minutes, hours, days, weeks, months, years).
3. Or select time zone conversion to convert a specific time from one time zone to another.
4. For unit conversion: enter the value and select the starting unit. All equivalent values in other units appear instantly.
5. For time zone conversion: enter a date and time, select the source time zone, and the tool displays the equivalent time in any target time zone — with daylight saving time applied automatically.

Time Unit Conversion Reference

Time Zone Reference

Converting Time Units: Key Relationships

The fundamental time unit relationships:

• 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 year ≈ 365.25 days = 8,766 hours = 525,960 minutes = 31,557,600 seconds

Note on months and years: these are not fixed. A calendar month has 28, 29, 30, or 31 days depending on the month and year. A year has 365 or 366 days. The converter uses averages for these (30.44 days per month, 365.25 days per year) which are accurate for most purposes but not exact for specific calendar months or years.

Converting Decimal Hours to Hours and Minutes

Decimal time (e.g., 2.5 hours) needs to be converted to hours and minutes for time displays:

Hours (integer part) = floor(2.5) = 2 hours

Minutes = (0.5 decimal remainder) × 60 = 30 minutes

So 2.5 hours = 2 hours 30 minutes. Another example: 1.75 hours = 1 hour 45 minutes (0.75 × 60 = 45 minutes). This conversion is needed for timesheet calculations — the work hours calculator performs this automatically.

Time Zones and UTC

UTC (Coordinated Universal Time) is the global reference standard for time. All time zones are defined as an offset from UTC — either behind (UTC−) or ahead (UTC+). The offset represents how many hours (and sometimes half-hours or quarter-hours) the local time differs from UTC.

UTC itself has no daylight saving time — it is always the same. When you need to communicate a specific moment unambiguously to someone in a different time zone, using UTC eliminates DST confusion.

ISO 8601 format: 2026-05-15T09:30:00Z — the Z suffix means UTC. This is the standard for computer systems, APIs, and international communication.

Daylight Saving Time

Daylight Saving Time (DST) — called Summer Time in the UK and EU — advances clocks by one hour during summer months to shift daylight to evening hours. Key points:

• UK (GMT → BST): Clocks go forward on the last Sunday in March at 1:00 AM (to 2:00 AM). Back on the last Sunday in October at 2:00 AM (to 1:00 AM). BST = UTC+1.
• EU (CET → CEST): Same schedule as the UK. CET (UTC+1) → CEST (UTC+2) in summer.
• US (EST → EDT): Second Sunday in March; first Sunday in November. Different schedule from Europe — there are periods where US/Europe time differences are off by an hour.
• Countries without DST: Japan, China, India, much of Asia and Africa, and most equatorial countries do not observe DST. The time difference between these countries and those that do observe DST changes twice a year.

Common Time Conversions for Scheduling

Converting common meeting times between major time zones (in standard time):

• 9:00 AM London (GMT/UTC) = 4:00 AM New York (EST) = 5:00 PM Tokyo (JST)
• 9:00 AM New York (EST) = 2:00 PM London (GMT) = 10:00 PM Tokyo (JST)
• 9:00 AM San Francisco (PST) = 12:00 PM New York (EST) = 5:00 PM London (GMT)

These offsets shift during DST transitions — the time converter accounts for DST automatically based on the selected date.

Common Questions

How many seconds are in a year?

In a standard 365-day year: 365 × 24 × 60 × 60 = 31,536,000 seconds. In a leap year (366 days): 31,622,400 seconds. The average Gregorian year (365.2425 days) = 31,556,952 seconds ≈ 31.56 million seconds. A useful approximation: roughly π × 10⁷ seconds per year (≈ 31.4 million) — accurate to within 0.5%.

What is the difference between GMT and UTC?

For everyday purposes, GMT and UTC are the same — both represent 0 hours offset from the prime meridian. Technically, UTC is a modern time standard based on atomic clocks with leap seconds added periodically to keep it within 0.9 seconds of mean solar time. GMT was the original standard based on astronomical observation and has no leap seconds. In practice, for scheduling and conversion purposes, they can be treated as identical.

Why do some time zones have half-hour or quarter-hour offsets?

Time zones were originally set to align roughly with local solar time (noon = sun at highest point). For large countries or regions, a half-hour offset better approximates local solar time than a full hour. India (UTC+5:30) and Sri Lanka (UTC+5:30) use half-hour offsets. Nepal (UTC+5:45) uses a quarter-hour offset. Australia has some states at UTC+9:30 (South Australia). These offsets are historical and political decisions, not purely scientific ones.