Week (wk)

Definition

Exactly 7 days.

History

The week is a seven-day cycle with ancient roots in Babylonian and Jewish tradition, tied to the seven classical planets and to religious observance. Unlike other time units it has no astronomical basis.

Where it is used

Weeks organise schedules and are used to count the length of pregnancies and projects.

Typical uses include schedules, pregnancy and projects.

Conversion pages

These pages convert week to or from another unit in time.

No conversion pages use this unit yet.

Other Time units

• Second (s)
• Minute (min)
• Hour (h)
• Day (d)
• Month (mo)
• Year (yr)

Sources

• BIPM SI BIPM SI Brochure (2019); the second is defined by the caesium-133 transition · Dataset reviewed Sep 18, 2026