Question 1

What is a Unix timestamp and why is it used?

Accepted Answer

Unix timestamp (epoch time) is seconds elapsed since January 1, 1970, 00:00:00 UTC (the "Unix epoch"). Example: 1609459200 = January 1, 2021, 00:00:00 UTC. Used because: timezone-independent (always UTC), easy arithmetic (1735689600 - 1609459200 = seconds between dates), compact storage (32-bit integer vs date string), universal standard across programming languages, sortable (higher number = later time). Negative values represent dates before 1970. 2038 problem: 32-bit timestamps overflow on January 19, 2038 (2,147,483,647 seconds) - solved with 64-bit integers. This tool converts between Unix time and readable formats instantly.

Question 2

What is the difference between seconds and milliseconds timestamps?

Accepted Answer

Unix timestamps use seconds by default (10 digits: 1609459200). JavaScript uses milliseconds (13 digits: 1609459200000) - multiply by 1000 to convert. Identify by length: 10 digits = seconds, 13 digits = milliseconds, 16 digits = microseconds (rare). Conversion: seconds × 1000 = milliseconds, milliseconds ÷ 1000 = seconds. Why milliseconds: higher precision for timing events, JavaScript Date() expects milliseconds, performance measurement needs sub-second accuracy. Use seconds for: dates, events, logs. Use milliseconds for: timestamps in code, performance metrics, precise event timing. This tool detects format automatically and converts between both.

Question 3

How do I handle timezones when working with Unix timestamps?

Accepted Answer

Unix timestamps are always UTC - timezone-agnostic. Display conversion adds timezone offset. Example: 1609459200 displays as "Jan 1, 2021 00:00 UTC" or "Dec 31, 2020 19:00 EST" (UTC-5). Storage best practice: always store UTC timestamps, convert to local timezone only for display. Avoid storing local time (ambiguous during DST transitions, moving users between zones). Common mistakes: comparing timestamps from different zones, forgetting DST shifts, using local time in databases. Solutions: use UTC everywhere in backend, convert to user timezone in frontend only, ISO 8601 format for APIs (2021-01-01T00:00:00Z). This tool shows timestamps in multiple timezones simultaneously.

Question 4

How do I convert Unix timestamps in different programming languages?

Accepted Answer

JavaScript: new Date(1609459200 * 1000) for seconds, Date.now() gets current milliseconds. Python: datetime.fromtimestamp(1609459200), time.time() for current. PHP: date("Y-m-d H:i:s", 1609459200), time() for current. MySQL: FROM_UNIXTIME(1609459200), UNIX_TIMESTAMP() for current. PostgreSQL: to_timestamp(1609459200), extract(epoch from now()). Java: new Date(1609459200L * 1000), System.currentTimeMillis(). Go: time.Unix(1609459200, 0), time.Now().Unix(). Remember: JavaScript/Java use milliseconds, most others use seconds. This tool generates code snippets for common languages.

Question 5

What is the Year 2038 problem and how does it affect timestamps?

Accepted Answer

32-bit signed integers max at 2,147,483,647 (January 19, 2038, 03:14:07 UTC) then overflow to negative (wraps to December 13, 1901). Affects: legacy 32-bit systems, embedded devices, old databases, C/C++ time_t on 32-bit platforms. Solutions: use 64-bit integers (supports year 292 billion+), update system libraries, upgrade to 64-bit OS, use unsigned 32-bit (extends to 2106). Modern systems: 64-bit by default (Python, JavaScript, Java long, PostgreSQL bigint). Check your system: if storing timestamps as 32-bit int, migrate to 64-bit now. This tool uses 64-bit timestamps supporting dates far beyond 2038.

Question 6

How do I calculate time differences using Unix timestamps?

Accepted Answer

Subtract timestamps to get seconds difference: 1735689600 - 1609459200 = 126230400 seconds. Convert to units: ÷ 60 = minutes, ÷ 3600 = hours, ÷ 86400 = days, ÷ 31536000 ≈ years. Example: 126230400 ÷ 86400 = 1,461 days = 4 years. For elapsed time: current_timestamp - event_timestamp. For future events: event_timestamp - current_timestamp. Add duration: timestamp + (days × 86400). Subtract duration: timestamp - (hours × 3600). Advantages: no timezone confusion, no DST issues, simple arithmetic. Disadvantages: doesn't account for months (varying lengths) or leap seconds. This tool calculates differences and shows results in multiple time units.

Question 7

What are common errors when working with Unix timestamps?

Accepted Answer

Mixing seconds and milliseconds - most common error. Use 10 digits (seconds) vs 13 (milliseconds). Timezone confusion - storing local time instead of UTC. Solution: always UTC. String comparison - "1609459200" > "999999999" lexically wrong. Use numbers. 32-bit overflow - timestamps after 2038. Use 64-bit. Leap seconds - Unix time ignores them (occasionally 61 seconds in minute). Not an issue for most apps. Float vs integer - precision loss in milliseconds. Use integers. Negative timestamps valid (pre-1970 dates). Forgetting to multiply/divide by 1000 when converting to JavaScript. This tool validates input and prevents common conversion errors.

Question 8

How do I format Unix timestamps for display in different regions?

Accepted Answer

Convert to Date object then format per locale. US: MM/DD/YYYY (01/15/2025), Europe: DD/MM/YYYY (15/01/2025), ISO 8601: YYYY-MM-DD (2025-01-15 - unambiguous). Time: 12-hour (3:30 PM) vs 24-hour (15:30). JavaScript: new Intl.DateTimeFormat("en-US").format(date). Libraries: date-fns, Moment.js (deprecated), Luxon, Day.js. Include timezone in display: "Jan 15, 2025 3:30 PM EST". Best practice: let user set preference or detect from browser locale (navigator.language). API responses: always use ISO 8601 with timezone: 2025-01-15T15:30:00Z. This tool formats timestamps in common regional formats with timezone support.

Question 9

What is Windows FILETIME and why do malware analysts need it?

Accepted Answer

Windows FILETIME is a 64-bit value representing 100-nanosecond intervals since January 1, 1601 00:00:00 UTC (Windows epoch). Used throughout Windows: PE file headers (TimeDateStamp), registry timestamps, NTFS metadata, event logs. Malware analysts need FILETIME because: PE compilation timestamps reveal when malware was built, registry modifications show persistence mechanisms, file system timestamps indicate infection timeline, Windows event correlation requires timestamp synchronization. Example: FILETIME 133774656000000000 (decimal) = 0x1DA3A7E8E3F0000 (hex) = 2024-12-04. Common in: exe/dll headers, Windows Registry forensics, memory dumps, NTFS  analysis. This tool converts FILETIME ↔ Unix ↔ human-readable for rapid malware timeline reconstruction.

Question 10

How do I convert between Windows FILETIME and Unix timestamps?

Accepted Answer

Conversion formula: Unix = (FILETIME / 10000000) - 11644473600, where 10000000 converts 100-ns intervals to seconds, 11644473600 is seconds between 1601 and 1970. Reverse: FILETIME = (Unix + 11644473600) × 10000000. Example: PE header TimeDateStamp 0x65703B80 (hex) = 1701892992 (Unix seconds) = Dec 6, 2023. FILETIME formats: decimal (18 digits: 133774656000000000), hexadecimal (0x prefix: 0x1DA3A7E8E3F0000). This tool supports both: select input format (Unix/FILETIME-decimal/FILETIME-hex), paste value, get all conversions instantly. Auto-detect: values > 100000000000000 assumed FILETIME, 0x prefix = hex. Batch mode: paste multiple timestamps for forensic timeline analysis.

Question 11

Where do I find FILETIME timestamps in malware analysis?

Accepted Answer

Common FILETIME locations: PE headers - IMAGE_FILE_HEADER.TimeDateStamp (Unix 32-bit, not FILETIME but needs conversion), debug directory timestamps. Registry - HKLM\SOFTWARE modification times, persistence keys (Run, RunOnce). NTFS -  (creation, modification, MFT change, access times),  timestamps. Event logs - Windows Event Log .evtx entries. Memory dumps - process creation times, thread start times. Prefetch files - execution timestamps. Tools extract these as hex/decimal - this converter translates to readable dates. Malware timeline: compile time → dropper execution → persistence installation → C2 communication. Analyst workflow: extract timestamps from tools (PEStudio, Registry Explorer, MFTECmd), paste into batch converter, build attack timeline.

Unix Epoch Time Converter - Timestamp to Date Tool

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Unix Timestamp

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