Units of Time in Spanish

'Unidades de tiempo'

sundial in Zaragoza, Spain
Reloj solar en Zaragoza, España. (Sundial in Zaragoza, Spain.). Photo by Juandc.com; licensed via Creative Commons.
by Gerald Erichsen
Gerald Erichsen, Spanish language expert, has created Spanish lessons for ThoughtCo and About Education since 1998.
Updated May 12, 2017

Need to know how to refer to a particular unit of time? Here are the most common ones in Spanish, listed from the shortest period of time to the longest:

  • el nanosegundo — nanosecond
  • el microsegundo — microsecond
  • el milisegundo — millisecond
  • el segundo — second
  • el minuto — minute
  • la hora — hour
  • el día — day
  • la semana, el septenario — week
  • la quincena — fortnight, two weeks (The term sometimes refers to a 15-day period or a half-month.)
  • el mes — month
  • el semestre — six months, half-year (The term can also refer to an academic semester.)
  • el año — year
  • el lustro — five years
  • el decenio, la década — 10 years, decade
  • el siglo — century
  • el milenio — millennium
  • el cron — million years
  • el eón — thousand million years, billion years in U.S. English (The term also can refer to an indefinitely long period of time.)

In addition, Spanish has a number of units of time that are seldom used, or are used in specific contexts. For example, bimestre and trimestre, are two-month and three-month periods, respectively, with similar month groupings possible. Similarly, bienio and septenio are two- and seven-year periods of time, respectively, with other groupings possible.