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About this tool
Convert mixed Unix timestamps and human dates in real time with timezone comparison, validation, history, search, and browser exports.
The Batch Timestamp Conversion Tool takes a pasted list of mixed Unix epochs and written dates and converts every row at once, deciding whether a number is seconds, milliseconds, microseconds or nanoseconds from its digit count. It is aimed at anyone reading raw logs, database dumps or API responses who needs the whole column in a readable timezone rather than one value at a time. Every row is converted through the IANA timezone database, and rows that cannot be parsed are listed separately instead of silently becoming a wrong date.
Open Batch Timestamp Conversion Tool on AltFTool — it loads instantly in your browser.
Paste your mixed Unix timestamps and human dates into the Batch Input box, separated by spaces or line breaks (up to 2,000 rows). Every row is detected, converted and validated as you type, and the Rows, Valid, Invalid and Success counters update with it.
Under Timezone Controls choose UTC / GMT, Local, IST - Kolkata, Pacific - Los Angeles, Eastern - New York, London or Tokyo, or type any zone into Custom IANA timezone — the badge reads Using <zone>, or Invalid timezone, falling back to UTC.
Read the results table (Row, Original Input, Converted Result, Format Type, Timezone, ISO / Detail, Status) and narrow it with Search rows, then use the Export Panel — Copy, CSV, TXT or JSON — to take the batch away. Save keeps it in History Section, where Restore loads it back.
Seconds, milliseconds, microseconds and nanoseconds are told apart automatically, so you do not have to divide by a thousand and hope.
Unparseable values get an invalid badge and their own validation list, with a success percentage across the batch.
Numbers become readable dates and written dates become epoch seconds, in the same table, from the same paste.
By digit count. Up to 10 digits is read as Unix seconds, 11-13 digits as milliseconds, 14-16 as microseconds, and anything longer as nanoseconds. All four are normalised to milliseconds internally before formatting.
2,000 rows per batch. Input is split on line breaks, tabs and spaces, surrounding quotes are stripped, and anything past the 2,000th value is ignored.
Any IANA zone name, such as Asia/Kolkata or Europe/London, entered in the custom field, plus quick picks for UTC, your detected local zone, Kolkata, Los Angeles, New York, London and Tokyo. An unrecognised zone name falls back to UTC with a visible warning rather than failing.
ISO 8601 plus common written forms including YYYY-MM-DD HH:mm:ss, MM/DD/YYYY, DD/MM/YYYY, YYYYMMDD, YYYYMMDDHHmmss, 'MMM D, YYYY' and RFC-style strings. A value that already carries a zone offset, Z, GMT or UTC is honoured as written; anything without one is read in the timezone you selected.