Unix timestamp: seconds, ms, µs or ns

finetype's datetime format reader reads a 10-digit integer as Unix seconds, a 13-digit integer as milliseconds, a 16-digit integer as microseconds and a 19-digit integer as nanoseconds.^[1] The reader picks a format only when at least 95% of the column's sampled non-null values match it.^[2][3] For these four formats the reader checks the digit count alone, not the date a value would decode to.^[1][4]

finetype's source describes a bare 10-digit integer as possibly an epoch, an identifier or a phone number, so it applies an epoch reading only when its model has already given the column a datetime type.^[5][6] finetype applies that reading only when at least 90% of the column's non-empty sampled values pass the chosen type's own validation rule.^[7][8]

Column names such as epoch, unix timestamp, epoch time and posix time point finetype to seconds, and epoch ms, unix ms and epoch milliseconds point it to milliseconds.^[9] A column name that no earlier header rule claims and that contains epoch or unix points to milliseconds when it also contains ms or milli, and to seconds when it does not.^[10] finetype declines a seconds or milliseconds hint from a column name when there are at least three non-empty values and 10% or fewer of them pass that type's validation rule.^[11][12]

Where the digit count and the column name disagree, decode a few values and check the dates against something you already know about the data. (Meridian's view)

The evaluation report in finetype's repository at release 0.6.66 measured release 0.6.60 on 2026-09-23.^[13] The report says its tables are generated by a separate tool that has drifted from the SQL harness it claims to mirror, and that a figure taken from it for publication must be its SQL headline.^[14] Until finetype publishes a measurement for each type, this page gives no figure for how often it mistakes one unit for another. (Meridian's view)