| UTC | — | Coordinated Universal Time |
| Local | — | Your timezone |
| ISO 8601 | — | Machine-readable standard |
| Unix | — | Seconds since 1970-01-01 |
| Unix (ms) | — | Milliseconds (Date.now()) |
| Unix (hex) | — | Hex. 0x80000000 = Y2K38 |
| GPS Week | — | Week + TOW, 18s ahead of UTC |
| TAI | — | Atomic time, UTC+37s, no leap sec |
| TT | — | Terrestrial Time = TAI+32.184s |
| Julian Date | — | Days since 4713 BC Jan 1 noon |
| MJD | — | JD − 2400000.5, epoch 1858 |
| ISO Week | — | Week date format |
| Day of Year | — | Ordinal date |
| Swatch .beat | — | @000–@999, no timezones |
| Seconds Today | — | Seconds since midnight UTC |
| Minutes Today | — | Minutes since midnight UTC |
| Loran-C Era | — | Days since 1958-01-01 |