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Sources and Accuracy
Time conversions use second as the reference unit. Calendar-style values such as average month and average Gregorian year are approximate by definition.
Displayed results are rounded for readability. The calculator keeps enough precision for everyday use and switches to scientific notation for very large or very small values. Last reviewed: 2026-05-21.
About These Units
week [wk]
Definition
The week is a calendar time unit equal to 7 days.
History
Seven-day weeks have long calendar and cultural use and are now common worldwide.
Current use
Weeks are used for work schedules, pregnancy tracking, planning cycles, subscriptions, and project timelines.
second [s]
Definition
The second is the SI base unit of time.
History
The second moved from astronomical definitions to an atomic definition for high precision.
Current use
Seconds are used in science, sports timing, computing, navigation, media, and everyday clocks.