Timestamp Converter and Epoch Time

Unix timestamps are used everywhere in programming. Learn how to work with them effectively.

What is Unix Timestamp?

Unix timestamp = seconds since January 1, 1970 (UTC)

Example: 1704067200 = January 1, 2024 at midnight UTC

Converting in JavaScript

// Current timestamp
const now = Math.floor(Date.now() / 1000);

// Timestamp to Date
const date = new Date(1704067200 * 1000);

// Date to timestamp
const timestamp = Math.floor(new Date('2024-01-01').getTime() / 1000);

Common Timestamp Formats

| Format | Example | |--------|---------| | Unix (seconds) | 1704067200 | | Unix (milliseconds) | 1704067200000 | | ISO 8601 | 2024-01-01T00:00:00Z | | UTC | Mon, 01 Jan 2024 00:00:00 GMT |

Time Zones

// Convert timestamp to specific timezone
const date = new Date(timestamp * 1000);
console.log(date.toLocaleString('en-US', { timeZone: 'America/New_York' }));

// Using Intl (modern approach)
const formatter = new Intl.DateTimeFormat('en-US', {
  timeZone: 'America/New_York',
  dateStyle: 'long',
  timeStyle: 'long'
});
console.log(formatter.format(date));

Useful Timestamp Operations

// Add 24 hours
const tomorrow = timestamp + (24 * 60 * 60);

// Get start of day
const startOfDay = Math.floor(new Date().setHours(0,0,0,0) / 1000);

// Get end of day
const endOfDay = Math.floor(new Date().setHours(23,59,59,999) / 1000);

Common Use Cases

1. Database storage - Store as integer for efficiency
2. API responses - Often use ISO 8601
3. File names - Include timestamp for sorting
4. Cache keys - Add timestamp for expiration

Handling Time Zones

// Best practice: Store in UTC, display in local
const utcTimestamp = 1704067200;
const localDate = new Date(utcTimestamp * 1000);

// Display to user in their timezone
const userTimezone = Intl.DateTimeFormat().resolvedOptions().timeZone;
console.log(`Timezone: ${userTimezone}`);

Quick Reference

| Description | Unix (seconds) | |-------------|---------------| | 1 minute | 60 | | 1 hour | 3600 | | 1 day | 86400 | | 1 week | 604800 | | 1 year (365 days) | 31536000 |

Conclusion

Always store timestamps in UTC. Convert to local time only when displaying to users. Use standard libraries for timezone handling.