Calendars and time
DUT1
Direct answer
DUT1 is the published correction UT1 minus UTC used to approximate Earth-rotation time from a UTC signal.
DUT1 is the broadcast difference between UT1 and UTC.
$0 today, then $12/month after 7 days. Cancel anytime.
At a glance
- Found in
- Calendars & Timekeeping
- Related
- Delta T, Earth Rotation Angle, Calendar, Julian Date
DUT1 is the broadcast difference between UT1 and UTC.
A cycle or timeline schematic for comparing the named timekeeping concept.
What does your own chart say about you?
Choose love, work or purpose. Your reading is written from your chart. Your reading uses your own birth details.
Walk through Alex’s whole example first
The Road of AgesSee the turning points of your whole life, from your birth date
See your road's shape
Prefer to explore first?
The Road of AgesThe turning points of your whole life, from your own chart
Walk my road
Free, by email
Your daily Almanac letter
One short letter at 7 each morning: the day’s theme read for your own chart, and one thing to do with it.
The story behind DUT1
Radio time services began broadcasting DUT1 corrections as atomic UTC and variable Earth rotation were coordinated.
DUT1 in practice: an example
Adding the signed DUT1 value to UTC gives an approximation of UT1 for the same instant.
Where readings of DUT1 go wrong
It is a mistake to reuse an old DUT1 value; it changes as Earth rotation evolves and is regularly updated.
Sources and editorial method
Research references used for this entry include:
- IERS Glossary: Universal Time (UT1) - Official definition of UT1 as Earth-rotation time and its publication as UT1-UTC.
- NIST: UTC(NIST) Time Scale - Official description of UTC realization, atomic time, and leap-second coordination.
- Source
- The Great Almanac Dictionary
- Category
- Calendars & Timekeeping
- Last updated
- 2026-09-26
Retrieve the current DUT1
A definition tells you what it is; your own birth chart tells you what it means for you. The Oracle casts your real chart and answers for your love, your work, and your year ahead, in conversation. It opens with the 7-day Seeker trial.
Speak with the OracleRelated terms
More in Calendars & Timekeeping
- GPS Time
- ISO Week Date
- Local Sidereal Time
- Proleptic Gregorian Calendar
- Solar Noon
- UTC Offset
- Barycentric Coordinate Time
- Civil Day
From the reference page to your own chart
Every word here
is in your own chart.
- A personal reading about love, work or purpose, written from your chart
- A practical next step to consider
- It opens with 7 days free, with the AI Oracle and daily guidance
$0 today, then $12/month after 7 days. Cancel anytime.
Common questions
What is DUT1?
DUT1 is the published correction UT1 minus UTC used to approximate Earth-rotation time from a UTC signal.
What do people get wrong about DUT1?
It is a mistake to reuse an old DUT1 value; it changes as Earth rotation evolves and is regularly updated.
Free, by email
The Almanac, in your inbox at 7
One short letter at 7 each morning: the day’s theme read for your own chart, and one thing to do with it.
