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Unix Time Converter

Free Unix time Converter for numeral systems units. Enter a value to see equivalent measurements across systems. Free to use with no signup required.

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Unit Conversion

Unix Time Converter

Convert Unix timestamps (epoch time) to human-readable dates and vice versa. Supports seconds and millisecond timestamps.

Last updated: December 2025

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Accepts seconds (10 digits) or milliseconds (13 digits)

Human-Readable Date
Sun, 17 May 2026 10:17:02 GMT
Unix Seconds
1779013022
Unix Milliseconds
1779013022000
ISO 8601
2026-05-17T10:17:02.000Z
UTC String
Sun, 17 May 2026 10:17:02 GMT
Local Time
5/17/2026, 2:47:02 PM
Time Since Epoch
20,590
days
10
hours
17
min
2
sec
Your Result
Unix 1779013022 = Sun, 17 May 2026 10:17:02 GMT
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Understand the Math

Formula

Unix Timestamp = seconds since January 1, 1970 00:00:00 UTC

Unix time counts the number of seconds elapsed since the Unix epoch (January 1, 1970, 00:00:00 UTC). Positive values represent dates after the epoch, negative values represent dates before it. Millisecond timestamps multiply by 1000 for sub-second precision.

Last reviewed: December 2025

Worked Examples

Example 1: Convert a Specific Timestamp

What date and time does Unix timestamp 1000000000 represent?
Solution:
1,000,000,000 seconds after Jan 1, 1970 00:00:00 UTC = 11,574 days, 1 hour, 46 minutes, 40 seconds = September 9, 2001 01:46:40 UTC
Result: Unix 1000000000 = September 9, 2001 01:46:40 UTC

Example 2: Date to Unix Timestamp

Convert July 20, 1969 (Moon landing) to a Unix timestamp.
Solution:
July 20, 1969 20:17:00 UTC is before the epoch Difference = -14,182,980 seconds Negative timestamps represent dates before Jan 1, 1970
Result: July 20, 1969 20:17:00 UTC = -14182980
Expert Insights

Background & Theory

The Unix Time Converter applies the following established principles and formulas. Unit conversion is the process of expressing a quantity in a different unit of measurement while preserving its physical meaning. At the foundation of modern measurement lies the International System of Units (SI), which defines seven base units: the meter for length, kilogram for mass, second for time, ampere for electric current, kelvin for thermodynamic temperature, mole for amount of substance, and candela for luminous intensity. All other units, called derived units, are defined as algebraic combinations of these seven. Dimensional analysis is the principal method for performing unit conversions. By treating units as algebraic quantities that can be multiplied, divided, and cancelled, a conversion factor chain allows a value expressed in one unit to be rewritten in another without altering its physical magnitude. For example, to convert 60 miles per hour to meters per second, one multiplies by a chain of conversion factors each equal to one: (1609.34 m / 1 mile) ร— (1 hour / 3600 s). Metric prefixes enable compact expression of quantities across extreme ranges of magnitude. Standard prefixes span from nano (10^-9) through micro (10^-6) and milli (10^-3) up through kilo (10^3), mega (10^6), and giga (10^9), and beyond in both directions. These prefixes are strictly multiplicative and apply consistently to any SI base or derived unit. Temperature conversions require affine transformations rather than simple scaling. To convert Celsius to Fahrenheit the formula is ยฐF = (ยฐC ร— 9/5) + 32, while the conversion to the absolute Kelvin scale is K = ยฐC + 273.15. These formulas reflect the different zero points and degree-size conventions of each scale. Significant figures govern how precision is preserved through calculations. A result should not express more precision than the least precise input value permits. In digital storage, IEEE and IEC standards distinguish between decimal prefixes (kilobyte = 1000 bytes) and binary prefixes (kibibyte = 1024 bytes), a distinction that has practical consequences for how storage capacity is reported by manufacturers versus operating systems. Unit coherence โ€” ensuring that all quantities in an equation share a consistent unit system โ€” is essential for obtaining correct results.

History

The history behind the Unix Time Converter traces back through the following developments. Human beings have been measuring and comparing quantities since before recorded history. The earliest known measurement units were body-based: the cubit (the distance from elbow to fingertip), the foot, the hand, and the digit. The furlong originated as the length of a furrow a team of oxen could plow without resting. These anthropomorphic standards were practical for local use but differed between regions and kingdoms, creating persistent difficulties in trade and construction. The ancient Egyptians standardized the royal cubit at approximately 52.4 centimeters and distributed calibrated granite rods to ensure consistency across building projects, including the pyramids. Roman engineers used the mile (mille passuum, one thousand double paces) and spread these standards throughout their empire via road networks. Despite these efforts, measurement diversity persisted across medieval Europe, hampering commerce. The French Revolution created political will for radical standardization. In 1795 France officially adopted the metric system, defining the meter as one ten-millionth of the distance from the equator to the North Pole along the Paris meridian. This gave the world its first fully decimal, rationally constructed measurement system. The Metre Convention of 1875 established the International Bureau of Weights and Measures (BIPM) in Sevres, France, creating a permanent international body to maintain physical artifact standards and coordinate global metrology. For over a century, the kilogram was defined by a platinum-iridium cylinder locked in a vault near Paris. In 1999, a stark demonstration of what unit inconsistency costs occurred when NASA's Mars Climate Orbiter was lost because one engineering team used pound-force seconds while another used newton seconds. The spacecraft entered the Martian atmosphere at the wrong angle and was destroyed, at a cost of 327 million dollars. In 2019 the SI underwent its most significant revision, redefining all seven base units in terms of fixed numerical values of fundamental physical constants such as the speed of light, Planck's constant, and the elementary charge. This eliminated any reliance on physical artifacts and made the measurement system permanently stable and universally reproducible.

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Frequently Asked Questions

Unix time, also called epoch time or POSIX time, is a system for tracking time as a single number: the count of seconds that have elapsed since January 1, 1970 at 00:00:00 UTC, not counting leap seconds. This date is known as the Unix epoch. For example, a Unix timestamp of 1700000000 represents November 14, 2023 at 22:13:20 UTC. Unix time is widely used in programming, databases, and operating systems because it provides a simple, unambiguous, timezone-independent way to represent a moment in time.
Standard Unix timestamps count seconds since the epoch and are typically 10 digits long (as of 2024). Millisecond timestamps multiply by 1000 to include fractional seconds, making them 13 digits long. JavaScript uses milliseconds by default with Date.now(), while languages like Python and PHP use seconds. Many APIs and databases accept both formats. This converter automatically detects whether your input is in seconds or milliseconds based on the digit count.
Unix timestamps are always in UTC and are not affected by time zones. A timestamp of 1700000000 represents the exact same moment worldwide, regardless of the local time zone. When you convert a Unix timestamp to a human-readable date, you must specify which time zone to display it in. This is why Unix timestamps are ideal for storing dates in databases that serve users across different time zones, as the conversion to local time happens at display time.
You may use the results for reference and educational purposes. For professional reports, academic papers, or critical decisions, we recommend verifying outputs against peer-reviewed sources or consulting a qualified expert in the relevant field.
All calculations use established mathematical formulas and are performed with high-precision arithmetic. Results are accurate to the precision shown. For critical decisions in finance, medicine, or engineering, always verify results with a qualified professional.
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
Educational Note: This calculator is provided for educational and informational purposes. Results are based on the formulas and inputs provided. Always verify important calculations independently. NovaCalculator processes calculator inputs client-side; optional analytics follow visitor consent settings. ยฉ 2024โ€“2026 NovaCalculator.

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Formula

Unix Timestamp = seconds since January 1, 1970 00:00:00 UTC

Unix time counts the number of seconds elapsed since the Unix epoch (January 1, 1970, 00:00:00 UTC). Positive values represent dates after the epoch, negative values represent dates before it. Millisecond timestamps multiply by 1000 for sub-second precision.

Worked Examples

Example 1: Convert a Specific Timestamp

Problem: What date and time does Unix timestamp 1000000000 represent?

Solution: 1,000,000,000 seconds after Jan 1, 1970 00:00:00 UTC\n= 11,574 days, 1 hour, 46 minutes, 40 seconds\n= September 9, 2001 01:46:40 UTC

Result: Unix 1000000000 = September 9, 2001 01:46:40 UTC

Example 2: Date to Unix Timestamp

Problem: Convert July 20, 1969 (Moon landing) to a Unix timestamp.

Solution: July 20, 1969 20:17:00 UTC is before the epoch\nDifference = -14,182,980 seconds\nNegative timestamps represent dates before Jan 1, 1970

Result: July 20, 1969 20:17:00 UTC = -14182980

Frequently Asked Questions

What is Unix time (epoch time)?

Unix time, also called epoch time or POSIX time, is a system for tracking time as a single number: the count of seconds that have elapsed since January 1, 1970 at 00:00:00 UTC, not counting leap seconds. This date is known as the Unix epoch. For example, a Unix timestamp of 1700000000 represents November 14, 2023 at 22:13:20 UTC. Unix time is widely used in programming, databases, and operating systems because it provides a simple, unambiguous, timezone-independent way to represent a moment in time.

What is the difference between Unix timestamps in seconds and milliseconds?

Standard Unix timestamps count seconds since the epoch and are typically 10 digits long (as of 2024). Millisecond timestamps multiply by 1000 to include fractional seconds, making them 13 digits long. JavaScript uses milliseconds by default with Date.now(), while languages like Python and PHP use seconds. Many APIs and databases accept both formats. This converter automatically detects whether your input is in seconds or milliseconds based on the digit count.

How do time zones affect Unix timestamps?

Unix timestamps are always in UTC and are not affected by time zones. A timestamp of 1700000000 represents the exact same moment worldwide, regardless of the local time zone. When you convert a Unix timestamp to a human-readable date, you must specify which time zone to display it in. This is why Unix timestamps are ideal for storing dates in databases that serve users across different time zones, as the conversion to local time happens at display time.

How do I get the most accurate result?

Enter values as precisely as possible using the correct units for each field. Check that you have selected the right unit (e.g. kilograms vs pounds, meters vs feet) before calculating. Rounding inputs early can reduce output precision.

Can I use the results for professional or academic purposes?

You may use the results for reference and educational purposes. For professional reports, academic papers, or critical decisions, we recommend verifying outputs against peer-reviewed sources or consulting a qualified expert in the relevant field.

Can I use Unix Time Converter on a mobile device?

Yes. All calculators on NovaCalculator are fully responsive and work on smartphones, tablets, and desktops. The layout adapts automatically to your screen size.

References

Reviewed by Manoj Kumar, Mathematics Educator ยท Editorial policy