What is the current TAI-UTC offset?

The current cumulative TAI-UTC offset is +37 seconds and has been unchanged since 2017-01-01.

DUT1 is the difference UT1−UTC, entered here as an estimate in seconds.

What UTC format should I enter?

Enter an ISO 8601 instant, such as 2026-08-10T12:00:00Z.

Which time scales does conversion include?

Conversion includes TAI, GPS, UT1, and Unix/POSIX time, along with leap-second status.

Does the tool retrieve live DUT1 data?

No. DUT1 is an input estimate; consult the official IERS Bulletin A for the precise current value.

Elysia Tools

Navigation

Date & Time

Leap Second Table — IERS DUT1, TAI-UTC Offset & Cross-System Time

IERS leap-second history (27 insertions since 1972), current TAI-UTC offset (+37 s), DUT1 (UT1-UTC) notes, and POSIX/NTP/GPS/TAI/UT1 cross-system conversion for a given UTC instant

Details

What this tool helps you do

For satellite ground-station operators, astronomers, HFT clock-sync engineers, and GNSS researchers. Shows the 27 IERS leap-second insertion events since 1972-01-01 and the cumulative TAI-UTC offset (currently +37 s, unchanged since 2017-01-01). Conversion mode: enter a UTC instant (and an optional DUT1 estimate) to get TAI = UTC + offset, GPS = UTC + (offset−19), UT1 = UTC + DUT1, the Unix/POSIX timestamp, and the leap-second status for that instant. Data from IANA leap-seconds.list / NIST / IERS. Pure local, deterministic, no network — DUT1 is live data (Bulletin A, weekly); here it is an estimated input, consult the official bulletin for the precise value.

Execution

Run this tool

Fill in the form, run the tool, and review the result in one place.

Result

Ready for a run

Run the tool to preview files, text, structured data, or streamed output here.

Samples

Leap Second Table — IERS DUT1, TAI-UTC Offset & Cross-System Time

What this tool helps you do

Run this tool

Prepared example runs

Inputs

Result

Examples that match this tool

Continue with connected tools and hubs

Prepared example runs

Inputs

Result

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Review the IERS leap-second history

2. Convert a historical UTC instant from 1995

FAQ

Time Zone Workflow Scheduler ICS Samples

WebRTC Real-Time Communication Samples

NATS Message System Samples

Android Date & Time Java Samples

Holiday Calculator

Work Hours Calculator

A/B Test Significance Calculator

Capacitor Series / Parallel / Reactance Calculator