Current Time (Live)

Unix (seconds): 0

Unix (milliseconds): 0

ISO 8601: -

Local Time: -

▸ Unix Timestamp

▸ Human-Readable Formats

UTC: -

ISO 8601: -

Local Time: -

Locale String: -

                                Relative Time:
                                -
                            

▸ Date & Time

Date Time Timezone

▸ Unix Timestamps

Seconds: -

Milliseconds: -

▸ Timestamp in Multiple Timezones

▸ Calculate Time Difference

From

▸ Batch Conversion

Input (one timestamp per line)

Format:

Output

▸ Add/Subtract Time

+ Add − Subtract

Start Time (Unix)

Days

Hours

Minutes

Seconds

⏰ What is a Unix Timestamp?

A Unix timestamp (also known as Epoch time or POSIX time) represents the number of seconds that have elapsed since January 1, 1970 00:00:00 UTC—a moment called the Unix Epoch. It's a single integer that increases by one every second.

Because it's just a number, it's incredibly efficient for computers to store, sort, and calculate dates, regardless of timezones. When you convert 1735689600 to a human-readable date, your device applies your local timezone offset to show you the correct local time.

Why developers use Unix timestamps:

Timezone Independence: The same timestamp means the same instant worldwide
Easy Calculations: Add 86400 to get tomorrow, subtract 3600 for an hour ago
Storage Efficiency: Just 4-8 bytes for any date in history or future
Sorting: Numeric comparison is faster than parsing date strings
API Compatibility: The universal format most APIs expect and return

🛠️ How to Use This Tool

Unix → Human

Paste any Unix timestamp (seconds or milliseconds) to see it converted to multiple human-readable formats: UTC, ISO 8601, local time, and relative time ("2 hours ago").

Human → Unix

Select a date, time, and timezone to generate the corresponding Unix timestamp in both seconds and milliseconds.

Timezones

Enter a timestamp to see what time it represents across 8 major world timezones simultaneously. Perfect for coordinating across distributed teams.

Relative Time

Calculate the exact difference between two timestamps. Great for debugging time-based logic or understanding log sequences.

Duration

Add or subtract days, hours, and minutes from a starting timestamp. Useful for calculating expiration times, scheduling, or "what time will it be in 3 days?"

Batch

Convert multiple timestamps at once. Paste a list (one per line) and get them all converted to your chosen format. Export as CSV for spreadsheets.

⚠️ Common Gotchas

Seconds vs. Milliseconds

The most common timestamp bug: mixing up seconds (10 digits) and milliseconds (13 digits).

Python, PHP, Ruby, SQL: Use seconds (e.g., 1736140800)
JavaScript, Java: Use milliseconds (e.g., 1736140800000)

Symptom: If your date shows 1970 (or year 54000+), you likely need to multiply or divide by 1000.

The Year 2038 Problem

32-bit signed integers max out at 2,147,483,647. Unix time will hit this on January 19, 2038 at 03:14:07 UTC. One second later, 32-bit systems will wrap to December 13, 1901. Most modern systems use 64-bit integers, which won't overflow for 292 billion years.

Daylight Saving Time

DST creates two types of problems: hours that happen twice (when clocks fall back) and hours that don't exist (when clocks spring forward). Always store in UTC to avoid these issues—convert to local time only for display.

Leap Seconds

Unix time ignores leap seconds by definition. A day is always exactly 86,400 seconds. Real-world clocks occasionally add a 61st second to stay synchronized with Earth's rotation, but Unix timestamps just keep counting linearly.

❓ Frequently Asked Questions

Why January 1, 1970?

Historical convention. Unix was being developed in the early 1970s, and the designers needed a reference point. 1970 was recent, round, and practical for the systems of that era. It stuck.

Can timestamps be negative?

Yes. Negative Unix timestamps represent dates before 1970. For example, -86400 is December 31, 1969. Most modern systems handle this correctly.

Why use UTC instead of local time?

Consistency. UTC never changes—no DST, no political timezone adjustments. Store everything in UTC, convert to local time only when displaying to users. This prevents countless bugs.

How do I handle timezone conversions in code?

Use libraries. JavaScript has Intl.DateTimeFormat. Python has pytz or zoneinfo. Never try to manually add/subtract hour offsets—DST rules are complex and change frequently.

What's ISO 8601?

The international standard for date/time strings. Format: 2026-01-23T14:30:00Z. The "T" separates date and time, "Z" means UTC. Use this when you need a human-readable string that's also unambiguous and sortable.

TIME Timestamp Converter