Measure Converter

Did You Know?

A second was once defined as 1/86,400 of a solar day but is now based on atomic clocks using cesium vibrations. Leap seconds are added to keep Earth’s slowing rotation in sync.

Leap seconds are added to keep Earth’s slowing rotation in sync.

The shortest measurable time is a zeptosecond (10⁻²¹ seconds)—light takes 247 zeptoseconds to cross a hydrogen molecule!

Quick Reference

• 1 s = 1000 ms
• 1 min = 60 s
• 1 h = 60 min
• 1 d = 24 h
• 1 wk = 7 d
• 1 mo ≈ 30.44 d
• 1 yr ≈ 365.25 d