Problems arise when when using metric time. Values below 10-3 and above 103 quickly become impractical for measuring human activities.
|Multiple||Name of Unit||Seconds||Minutes||Hours||Days||Years|
|105||metric day**||100,000||1 666.667||27.778||1.158||0.003|
|107 and 108 are currently not defined|
| * The "myria" prefix was abrogated (officially retired) in 1960.|
** "Metric day" is an unofficial/ad hoc definition.
Likewise, adding metric prefixes to units of time such as the week also results in values that are difficult to use. Examples:
- Megaweek: 1,000,000 weeks (230,137.32 months or 19,178.11 years or 1.917 millenia)
- Kiloday: 1,000 days (33.333 months or 2.740 years)
- Decafortnight: 10 fortnights (140 days or 4.667 months or 0.384 years)
- Teramonth: 1,000,000,000,000 months (83,333,333,333 years or 83.33 aeons)
- Novemquadraweek: 73 days (343 days or 49 weeks or 0.940 years)
In the last example, the name alone is more cumbersome than simply saying "forty-nine weeks".
While the metric system provides a uniform way of counting time, implementing it requires a significant number of decimal places used for the values and becomes cumbersome, especially when compared with measurements based on the rotation of the Earth on its axis and around the sun, such as the day, year and longer measurements like the millennium.
For example, there are 295 days before October 23 in a year that is not a leap year, which equals 25,488,000 seconds. 2:57 p.m. and 47 seconds on October 23 adds 1,126,667 seconds, for a total of 26,614,667 seconds. Expressing this as gigaseconds equals 0.00026614667 gigaseconds.