Time Converter
Convert between seconds, minutes, hours, days, weeks, and years.
How it works
This converter handles the everyday units of time — seconds, minutes, hours, days, weeks, and years — converting your value to seconds (the base unit) first, then from seconds into your target unit.
The relationships between the smaller units are fixed and universal: 60 seconds make a minute, 60 minutes make an hour, and 24 hours make a day — giving 86,400 seconds in a day. A week is simply 7 days, or 604,800 seconds.
Years are the one unit in this list that isn't perfectly fixed: a calendar year is commonly treated as 365 days for conversion purposes, though the actual solar year is about 365.2425 days (which is why leap years exist — an extra day roughly every four years keeps the calendar aligned with Earth's orbit over time).
Because of this, a "1 year" conversion using 365 days is an approximation, not exact math — most everyday time conversions treat this as close enough, but the small fractional difference is exactly what accumulates into the need for occasional leap years and, in even rarer cases, leap seconds to keep clocks synchronized with Earth's rotation.
Converting through seconds as a common base (rather than converting directly between every possible pair of units) is the standard approach in unit conversion generally — it means only two conversion factors are needed per unit (to and from the base) instead of a separate factor for every possible pairing.
This kind of conversion comes up often in practical contexts: converting a project timeline from weeks to days for a schedule, converting a song or video duration from seconds to minutes, or converting an age or duration from years to days for a more granular comparison.
The base-60 structure behind seconds, minutes, and hours has ancient roots — it traces back to Babylonian mathematics, which used a base-60 (sexagesimal) numbering system because 60 divides evenly by many small numbers (2, 3, 4, 5, 6, 10, 12, 15, 20, 30), making it convenient for calculations and fractions long before decimal systems became standard.
By contrast, the day-week-year structure of time is tied to astronomical cycles rather than arithmetic convenience: a day corresponds to Earth's rotation, a year to Earth's orbit around the Sun, and a week is a human convention with no direct astronomical basis, which is part of why it doesn't divide evenly into a year (52 weeks account for only 364 of a year's 365 or 366 days).
How many seconds are in a day?
86,400 seconds.
How many seconds are in a year?
Approximately 31,536,000 seconds (365 days), though this calculator uses 365 days as the standard year length for conversion purposes.
Why isn't a year exactly 365 days in reality?
The actual solar year is about 365.2425 days — the extra fraction is why leap years (with an added day) occur roughly every four years to keep the calendar aligned with Earth's orbit.
How many minutes are in a week?
10,080 minutes (7 days × 24 hours × 60 minutes).
Why does this converter go through seconds instead of converting units directly?
Using a common base unit (seconds) means only two conversion factors are needed per unit, rather than a separate factor for every possible pair of units — a simpler and more standard approach.
How many hours are in a week?
168 hours (7 days × 24 hours).
Can I convert fractional values, like 2.5 hours?
Yes — enter any decimal value and it converts proportionally, so 2.5 hours converts to 150 minutes or 9,000 seconds.
How precise are these time conversions?
Fully precise for the fixed units (seconds through weeks); the year conversion is an approximation based on a 365-day year, as explained above.
Why do we use 60 seconds per minute instead of a round number like 100?
It traces back to the ancient Babylonian base-60 numbering system, chosen because 60 divides evenly by many small numbers, making it convenient for calculation long before decimal systems became standard.
Why doesn't a week divide evenly into a year?
A week is a human convention without a direct astronomical basis, while a year is tied to Earth's orbit — 52 weeks only account for 364 of a year's 365 (or 366) days, leaving a remainder.