Leap Second Calculator
Calculate cumulative leap seconds and offsets between UTC, TAI, and GPS time scales for any date.
Recent Leap Seconds
Dec 31, 2016+1s (Total: 27)
Jun 30, 2015+1s (Total: 26)
Jun 30, 2012+1s (Total: 25)
Dec 31, 2008+1s (Total: 24)
Dec 31, 2005+1s (Total: 23)
Dec 31, 1998+1s (Total: 22)
Jun 30, 1997+1s (Total: 21)
Dec 31, 1995+1s (Total: 20)
Jun 30, 1994+1s (Total: 19)
Jun 30, 1993+1s (Total: 18)
Cumulative Leap Seconds
27
TAI - UTC
37s
GPS - UTC
18s
Time Information
Last Leap Second: December 31, 2016
Days Since Last: 3,435
Days Since Unix Epoch: 20,601
Total Leap Seconds (all time): 27
Leap Seconds by Decade
1970s
9
1980s
6
1990s
7
2000s
2
2010s
3
Note: Leap seconds are added to keep UTC within 0.9 seconds of UT1 (Earth rotation time). They are announced by IERS and typically added on June 30 or December 31. The last leap second was added on December 31, 2016.
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Editorial Note
MyCalcBuddy Editorial Team
This page is maintained as an educational calculator reference.
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Formula Source: Standard Mathematical References
by Various
🔄Last reviewed: May 2026
✓Formula checks are based on standard references and internal QA review.