Oihana PHP Standards

isIso8601Time.php

Table of Contents

Functions

isIso8601Time()  : bool
Validates whether a string is a valid ISO 8601 time format.

Functions

isIso8601Time()

Validates whether a string is a valid ISO 8601 time format.

isIso8601Time(string $time[, bool $strict = false ]) : bool

This function checks if a given string conforms to the ISO 8601 time specification. ISO 8601 time format includes:

  • Optional 'T' prefix
  • Hours (00-23)
  • Optional minutes (00-59)
  • Optional seconds (00-59, can be fractional)
  • Optional timezone offset (Z for UTC or ±HH:MM)

Examples of valid formats:

  • "T14:30:00Z" → 14:30:00 UTC
  • "T08:15:30+02:00" → 08:15:30 in UTC+2
  • "T23:59:59" → 23:59:59 local time (no offset)

Rules:

  • Hours must be 00-23
  • Minutes and seconds, if present, must be 00-59
  • Fractional seconds are allowed
  • Timezone, if present, must be 'Z' or ±HH:MM
Parameters
$time : string

The time string to validate

$strict : bool = false

If true, validates strictly with regex; if false, uses DateTimeImmutable parser (default: false)

Tags
example 
isIso8601Time('T14:30:00Z');       // true
isIso8601Time('T08:15:30+02:00');  // true
isIso8601Time('T23:59:59');        // true
isIso8601Time('14:30:00');         // false (missing T)
isIso8601Time('INVALID');           // false

// Strict mode validation
isIso8601Time('T14:30:00.123Z', true); // true (fractional seconds allowed)
isIso8601Time('T14:60:00', true);      // false (invalid minutes)
link

ISO 8601 Time specification

PHP DateTimeImmutable documentation
author

Marc Alcaraz (ekameleon)

since
1.0.1
Return values
bool —

True if the string is a valid ISO 8601 time, false otherwise

On this page

Search results