Time is something we deal with constantly in software, but very few people stop to think about how systems actually store it. That’s where epoch time comes in.
Epoch time (also called Unix time) is a way of representing time as a single number. Instead of dates, months, leap years, or time zones, time is stored as the number of seconds elapsed since January 1, 1970, 00:00:00 UTC.
For example:
0 → Jan 1, 1970, 00:00:00 UTC
1700000000 → Some moment in 2023
Just a number. No formatting. No ambiguity.
Why Epoch Exists
Computers are bad at understanding calendars. Humans invented months with different lengths, leap years, daylight saving changes, and time zones. Epoch strips all of that away.
A simple counter:
seconds since a fixed starting point
This makes time:
Easy to store
Easy to compare
Easy to calculate differences
Example:
If one event happened at 1700000100 and another at 1700000200, you immediately know the gap is 100 seconds. No parsing required.
Why Epoch Time Is So Widely Used
Epoch time quietly powers most systems you use every day.
Common uses:
Database timestamps
API request signing
Token expiry (JWT, OAuth)
Log ordering
Cache invalidation
Distributed systems
Example:
token_expires_at = current_epoch + 3600
That logic works the same in Python, JavaScript, Go, or any other language.
Interesting Facts About Epoch
1970 was chosen for practicality
Unix was developed around that time, so starting from 1970 avoided negative numbers for “current” dates.Epoch avoids timezone bugs
Epoch is always UTC. Time zones are applied only when displaying time to humans.The Year 2038 problem is real
Systems using 32-bit signed integers will overflow on
Jan 19, 2038, 03:14:07 UTC.
Modern systems mostly use 64-bit integers and are safe.During debugging, developers often convert raw epoch values into readable dates using simple converters available online, such as Epoch Tool(https://www.codeground.ai/epoch)
, to quickly make sense of logs and API responses.Epoch isn’t just seconds anymore
Many systems use:
milliseconds (JavaScript)
microseconds (databases)
nanoseconds (high-precision systems)
Epoch makes sorting trivial
Sorting timestamps as numbers is faster and safer than sorting date strings.
Epoch in Everyday Development
If you’ve ever:
Compared two timestamps
Checked if something expired
Calculated “time ago”
Synced events across servers
You’ve already relied on epoch time, even if you didn’t realize it.
Having a quick way to convert epoch values into readable dates (and back) becomes surprisingly useful when debugging logs, inspecting API responses, or validating timestamps during development.
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