Timestamp Batch Converter Free Online Tool 2026

Last updated March 22, 2026

Timestamp Batch Converter Examples

The Timestamp Batch Converter processes multiple timestamps simultaneously, converting between Unix timestamps, ISO 8601, and human-readable formats. Below are practical examples for log processing, data migration, and bulk conversion tasks.

Batch Unix Timestamp to ISO 8601

// Input (one timestamp per line):
1710504000
1710507600
1710511200
1710514800
1710518400

// Output (ISO 8601 UTC):
1710504000 → 2024-03-15T14:00:00Z
1710507600 → 2024-03-15T15:00:00Z
1710511200 → 2024-03-15T16:00:00Z
1710514800 → 2024-03-15T17:00:00Z
1710518400 → 2024-03-15T18:00:00Z

Millisecond Timestamps (13-digit)

// Input (millisecond Unix timestamps):
1710504000000
1710504060000
1710504120000
1710504180000

// Output:
1710504000000 → 2024-03-15T14:00:00.000Z
1710504060000 → 2024-03-15T14:01:00.000Z
1710504120000 → 2024-03-15T14:02:00.000Z
1710504180000 → 2024-03-15T14:03:00.000Z

// Auto-detection:
// 10-digit number → seconds (Unix timestamp)
// 13-digit number → milliseconds
// 16-digit number → microseconds
// 19-digit number → nanoseconds

ISO 8601 to Unix Timestamp

// Input (ISO 8601 dates):
2024-01-01T00:00:00Z
2024-03-15T14:30:00Z
2024-06-21T08:00:00+05:30
2024-12-31T23:59:59Z

// Output (Unix timestamps in seconds):
2024-01-01T00:00:00Z      → 1704067200
2024-03-15T14:30:00Z      → 1710505800
2024-06-21T08:00:00+05:30 → 1718929800  (converted to UTC first)
2024-12-31T23:59:59Z      → 1735689599

Log File Timestamp Conversion

// Server log with Unix timestamps:
1710504001 GET /api/users 200 45ms
1710504002 POST /api/orders 201 120ms
1710504005 GET /api/products 200 30ms
1710504010 DELETE /api/sessions 204 15ms
1710504015 GET /api/users 500 2ms

// After batch conversion (timestamps → ISO 8601):
2024-03-15T14:00:01Z GET /api/users 200 45ms
2024-03-15T14:00:02Z POST /api/orders 201 120ms
2024-03-15T14:00:05Z GET /api/products 200 30ms
2024-03-15T14:00:10Z DELETE /api/sessions 204 15ms
2024-03-15T14:00:15Z GET /api/users 500 2ms

Mixed Format Input (Auto-Detection)

// Input (mixed formats — auto-detected):
1710504000          // Unix seconds
1710504000000       // Unix milliseconds
2024-03-15          // Date only
2024-03-15T14:00:00Z  // ISO 8601 UTC
March 15, 2024      // Human-readable

// Output (all converted to ISO 8601 UTC):
1710504000          → 2024-03-15T14:00:00Z
1710504000000       → 2024-03-15T14:00:00.000Z
2024-03-15          → 2024-03-15T00:00:00Z
2024-03-15T14:00:00Z → 2024-03-15T14:00:00Z (unchanged)
March 15, 2024      → 2024-03-15T00:00:00Z

Timezone Conversion in Batch

// Input (UTC timestamps):
2024-03-15T14:00:00Z
2024-03-15T15:00:00Z
2024-03-15T16:00:00Z

// Convert to America/New_York (EDT, UTC-4 in March):
2024-03-15T14:00:00Z → 2024-03-15T10:00:00-04:00
2024-03-15T15:00:00Z → 2024-03-15T11:00:00-04:00
2024-03-15T16:00:00Z → 2024-03-15T12:00:00-04:00

// Convert to Asia/Tokyo (JST, UTC+9):
2024-03-15T14:00:00Z → 2024-03-15T23:00:00+09:00
2024-03-15T15:00:00Z → 2024-03-16T00:00:00+09:00  (next day!)
2024-03-15T16:00:00Z → 2024-03-16T01:00:00+09:00

CSV Output Format

// Batch converter CSV output:
original,unix_seconds,unix_ms,iso8601_utc,human_readable
1710504000,1710504000,1710504000000,2024-03-15T14:00:00Z,"March 15, 2024 2:00 PM UTC"
1710507600,1710507600,1710507600000,2024-03-15T15:00:00Z,"March 15, 2024 3:00 PM UTC"
1710511200,1710511200,1710511200000,2024-03-15T16:00:00Z,"March 15, 2024 4:00 PM UTC"

Database Export Normalization

// Legacy database export (timestamps in various formats):
user_id,created_at,last_login
1,1640000000,1709900000
2,2022-01-01 00:00:00,2024-03-08 10:30:00
3,Jan 1 2022,Mar 8 2024

// After batch normalization to ISO 8601 UTC:
user_id,created_at,last_login
1,2021-12-20T11:33:20Z,2024-03-08T10:13:20Z
2,2022-01-01T00:00:00Z,2024-03-08T10:30:00Z
3,2022-01-01T00:00:00Z,2024-03-08T00:00:00Z

Error Handling

// Input with invalid timestamps:
1710504000          // valid
not-a-timestamp     // ERROR: unrecognized format
9999999999999999    // ERROR: out of range
2024-13-45          // ERROR: invalid date (month 13)
1710504001          // valid

// Output:
1710504000  → 2024-03-15T14:00:00Z  ✓
not-a-timestamp → ERROR: unrecognized format  ✗
9999999999999999 → ERROR: timestamp out of valid range  ✗
2024-13-45  → ERROR: invalid date  ✗
1710504001  → 2024-03-15T14:00:01Z  ✓

// Valid: 3, Errors: 2, Total: 5

JavaScript Batch Conversion

// Process an array of timestamps
function batchConvert(timestamps, targetFormat = 'iso') {
  return timestamps.map(ts => {
    try {
      let date;
      if (typeof ts === 'number') {
        // Auto-detect seconds vs milliseconds
        date = ts > 1e12 ? new Date(ts) : new Date(ts * 1000);
      } else {
        date = new Date(ts);
      }
      if (isNaN(date.getTime())) throw new Error('Invalid date');
      return { original: ts, converted: date.toISOString(), error: null };
    } catch (e) {
      return { original: ts, converted: null, error: e.message };
    }
  });
}

batchConvert([1710504000, 1710507600, 'invalid']);
// [
//   { original: 1710504000, converted: '2024-03-15T14:00:00.000Z', error: null },
//   { original: 1710507600, converted: '2024-03-15T15:00:00.000Z', error: null },
//   { original: 'invalid',  converted: null, error: 'Invalid date' }
// ]

Common Use Cases

• Convert Unix timestamps in log files to readable dates
• Normalize timestamps from multiple data sources to UTC
• Migrate database timestamps between formats
• Convert API response timestamps for display
• Validate timestamp data quality in exports
• Batch convert timestamps to a specific timezone
• Generate CSV with original and converted timestamps for audit

Paste your timestamps (one per line) into the Timestamp Batch Converter, choose your output format and timezone, and download the converted results as CSV.