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Date & Time Converters

Unix timestamps, Excel serial dates, FILETIME, ISO 8601, cron, and calendar converters.

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Date tools Days between, age, week numbers, deadlines Time tools Timer, stopwatch, alarm, world clock, hours Converters (here) Unix, Excel, FILETIME, ISO 8601, cron

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Unix Timestamp Epoch seconds ↔ human-readable date FILETIME Converter Windows FILETIME / LDAP timestamp converter Excel Date Converter Excel serial date \u2194 calendar date ISO 8601 Converter ISO 8601 and RFC 2822 date formats Batch Timestamp Converter Convert many Unix timestamps at once Discord Timestamp Discord timestamp codes (R / t / T / d / D / f / F) Year 2038 Problem Y2038 epoch overflow explained with converter Roman Numeral Date Convert years and dates to Roman numerals Cron Calculator Next run times from a cron expression LDAP Timestamp Active Directory LDAP / FILETIME converter UUID Timestamp Extract time from UUID version 1 Hex Timestamp Converter Hexadecimal Unix timestamp converter Julian Day Number Julian Day Number (JDN) converter Modified Julian Date MJD converter for astronomy Ordinal Date YYDDD / YYYYDDD ordinal date converter Mayan Calendar Long Count / Mayan date converter Hebrew Date Converter Gregorian \u2194 Hebrew calendar dates Islamic Date Converter Gregorian \u2194 Hijri calendar dates French Republican Date French Revolutionary calendar converter RFC 2822 Date RFC 2822 / HTTP-date formatter and parser Persian / Jalali Date Convert between Gregorian and Persian (Jalali / Solar Hijri) dates Julian ↔ Gregorian Convert historical Julian calendar dates to Gregorian and back Date Format Converter Convert one date between US, European, ISO 8601, and written formats Japanese Era Converter Convert between Gregorian dates and Japanese era years (Reiwa, Heisei, Showa) Snowflake ID Timestamp Decode the timestamp stored inside a Discord or X (Twitter) snowflake ID WebKit / Chrome Timestamp Convert Chrome and WebKit timestamps (microseconds since 1601) to dates Cocoa / Mac Absolute Time Convert Apple Cocoa and Core Data timestamps (seconds since 2001) to dates Coptic Date Converter Convert between Gregorian dates and the Coptic calendar Ethiopian Date Converter Convert between Gregorian dates and the Ethiopian calendar Thai Solar / Buddhist Era Convert Gregorian dates to Thai solar Buddhist Era (BE) dates and back Minguo (ROC) Date Convert between Gregorian dates and Taiwan Minguo (ROC) years Indian Saka Date Convert between Gregorian dates and the Indian national Saka calendar

The converters hub gathers timestamp, spreadsheet, and calendar-system tools that turn one time representation into another. Use it when a Unix epoch, Excel serial date, LDAP stamp, or cultural calendar date must become a civil date humans can read — or the reverse.

Unix and machine timestamps

Start with the Unix timestamp converter for everyday epoch seconds. Batch and hex variants help when logs arrive in bulk or hexadecimal form. Related pages cover the year 2038 boundary, LDAP timestamps, and UUID time fields for developers debugging storage formats.

Keep units explicit in notes: seconds versus milliseconds confuse more pipelines than any other timestamp mistake. Convert at the boundary of each system rather than nesting formats through three libraries.

Spreadsheet and standards

The Excel date converter handles serial numbers from spreadsheets. Windows FILETIME and ISO 8601 strings each have dedicated pages so imports do not silently shift by a day. Cron expression helpers decode schedules used by servers.

When a CSV lands with mixed date columns, convert each column once at import time. Re-encoding through multiple libraries often drops timezone offsets or adds a phantom day at month boundaries.

Cultural and astronomical day counts

Julian day numbers, modified Julian dates, ordinal dates, and Roman numeral date displays support research and archival workflows. Mayan, Hebrew, Islamic, and French Republican converters provide dual views with notes about tabular versus observational rules.

These pages show both the converted civil date and the source notation so you can verify against primary references. Lunar and religious calendars may differ by a day depending on local sighting rules — each page states which rule set it follows.

Ordinal date pages express a day as YYYY-DDD, a format common on shipping labels and manufacturing stamps. Pair an ordinal result with the matching month on monthly calendars when you need a human-readable grid for the same day.

When to leave this hub

If you need a countdown, stopwatch, or timesheet total, open the time tools hub. If you need days between civil dates, ages, or business-day spans, use date tools. Printable month grids remain at monthly calendars.

Each converter page explains accuracy limits in plain language. Treat browser results as practical aids for everyday engineering and study — not certified legal timekeeping for regulated systems without cross-checks.

Frequently asked questions

Which converter handles Unix epoch seconds?

The Unix timestamp page converts epoch seconds and milliseconds to readable datetime and back. Use batch or hex variants when logs contain many values or hexadecimal encoding. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.

Where do I decode Excel serial numbers?

The Excel date converter maps serial integers to calendar dates for both the 1900 and 1904 date systems. Match the system your spreadsheet or export uses. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.

What is the difference between FILETIME and LDAP timestamp?

Both often refer to the same 1601-based Windows tick format in Active Directory. The LDAP page adds attribute context; FILETIME covers general Windows API values. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.

When should I use ISO 8601 converter?

Use it for API strings, JSON fields, and email RFC 2822 headers that need normalized ISO output for sorting, storage, or comparison across services. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.

Are calendar converters on this hub?

Yes. Hebrew, Islamic, Mayan, Julian Day Number, and ordinal date tools live here alongside epoch converters. Civil date math without serial formats is on the date tools hub. Always confirm edge cases against primary sources when results affect legal, medical, or financial decisions.