Encoded output includes milliseconds as .000 when zero.

Values like 2024-01-01T12:00:00+02:00 parse when the browser supports them.

Date-only ISO strings parse at UTC midnight unless the browser treats them as local.

ISO 8601 Converter – Parse & Format Date-Time Strings

Work with API timestamps and log formats: paste an ISO string to read it, or pick a moment to copy canonical UTC ISO output.

Parse ISO string

Create ISO from datetime

Related tools

Parse mode uses the browser Date parser on your ISO input; encode mode converts a local picker value to toISOString().

Output UTC uses the Z suffix as produced by JavaScript’s ISO serializer.

Common variants with Z or numeric offsets are accepted when the browser can parse them.

Invalid or partial strings show an error rather than guessing.

Milliseconds?: Encoded output includes milliseconds as .000 when zero.
Offset strings?: Values like 2024-01-01T12:00:00+02:00 parse when the browser supports them.
Date only?: Date-only ISO strings parse at UTC midnight unless the browser treats them as local.
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