Validate an API timestamp
Check whether a timestamp returned by an API is valid and see its UTC representation.
Free • No signup • Fast
ISO8601 Validator
Supports date-only values, datetimes, fractional seconds and timezone offsets such as Z, +02:00 or +0200.
Valid ISO8601 value
This value matches a supported ISO8601 format.
Normalized value
2026-05-17T14:30:00+02:00
Timezone offset
+02:00
UTC value
2026-05-17T12:30:00.000Z
Unix seconds
1,779,021,000
Unix milliseconds
1,779,021,000,000
Related tools
- Timestamp Converter Convert Unix timestamps to readable dates and back.
- JSON Formatter Format and validate JSON payloads that often contain ISO date strings.
- Developer Tools Browse browser-based utilities for everyday web development.
How it works
Validate ISO8601 date and datetime strings, inspect timezone offsets and convert valid values to UTC and Unix timestamps.
Practical examples
Inspect timezone offsets
Compare values such as Z, +02:00 and +0200 to understand how they map to UTC.
Debug logs and database values
Paste timestamps from logs or database fields and convert them to Unix seconds and milliseconds.
FAQ
What is ISO8601?
ISO8601 is a standard way to write dates and times, commonly used in APIs, databases, logs and backend systems.
Does this validator send my data anywhere?
No. The validation runs in your browser, so pasted timestamps are not sent to an external server.
What happens when no timezone is provided?
A date-only value is treated as a calendar date. A datetime without an explicit timezone is accepted, but the UTC conversion is based on the parsed numeric fields rather than a named local timezone.
Try these tools
VAT Calculator
Add or remove VAT at 22%, 10% and 4%.
Unit Converter
Convert length, weight, temperature, volume, area, speed and pressure.
Percentage Calculator
Calculate percentages, discounts, increases and decreases.
Margin Calculator
Calculate profit and margin from cost and selling price.
Markup Calculator
Calculate percentage markup from product cost.
Net Salary Calculator
Estimate monthly take-home pay from gross annual income.
Inverse Discount Calculator
Find the original price from a discounted price and discount percentage.
JWT Decoder
Decode the header and payload of a JSON Web Token directly in your browser.
LLM Token Estimator
Estimate token usage and approximate cost for text used with AI models.
AI Cost Calculator
Estimate AI model API costs from tokens and daily request volume.
JSON Formatter
Format, validate, minify and copy JSON directly in your browser.
Base64 Encoder/Decoder
Encode and decode Base64 directly in your browser.
Unix Timestamp Converter
Convert Unix timestamps to readable dates and back.
URL Encoder/Decoder
Encode and decode URLs for query strings, APIs and redirects.
UUID Generator
Generate UUID v4 identifiers for APIs, databases, tests and software development.
Public IP Checker
Check your public IP, approximate geolocation and VPN information.