Unix Timestamp to Date (UTC & Local)

A Unix timestamp counts seconds (or milliseconds) since 1970-01-01T00:00:00Z. It has no timezone inside the number. Timezones appear only when you format it for humans.

Seconds vs milliseconds (again)

Digits (typical)	Unit
10	seconds
13	milliseconds

Feeding milliseconds into an API that expects seconds jumps the date into the far future. See also: seconds vs milliseconds.

UTC vs local display

• UTC string — same everywhere (…Z or +00:00).
• Local string — depends on the machine or the timezone you pick (e.g. Asia/Kolkata).

Same epoch → two clocks on the wall. If a log says 15:00 and your converter says 20:30, you are probably mixing local and UTC, not “wrong epoch math.”

Practical workflow

1. Count digits → pick seconds or ms.
2. Convert to an ISO UTC time first.
3. Only then project into the timezone you care about.
4. When comparing two systems, agree on UTC storage and localize only in the UI.

Use TryDevSnip Timestamp Converter

TryDevSnip Timestamp Converter converts epoch ↔ human dates in the browser, with a live clock. Paste privately — nothing is uploaded.

FAQ

Does the timestamp change when I fly to another country?

No. The integer is the same. Only the formatted local time changes.

Should APIs store UTC or local?

Store UTC (or epoch). Localize for display.

Why is my date off by 5:30?

That is a classic IST (+05:30) vs UTC display mismatch — check which side you formatted.