تبدیل یکاهای اندازه‌گیری
جدول تبدیل‌ها > زمان

| نام یکا | نشان | توضیحات | معادل در دستگاه بین‌المللی یکاها |
| --- | --- | --- | --- |
| atomic unit of time | au | ≡ شعاع بور/(α·c) | ≈ 2.418 884 254‎×۱۰−۱۷ s |
| Callippic cycle |   | ≡ 441 mo (hollow) + 499 mo (full) = 76 a of 365.25 d | = 2.398 3776‎×۱۰۹ s |
| سده | c | ≡ 100 a (see below for definition of year length) | = 100 years |
| روز | d | = 24 h | = 1440 min = ۸۶۴۰۰ s |
| روز (sidereal) | d | ≡ Time needed for the Earth to rotate once around its axis, determined from successive transits of a very distant astronomical object across an observer's meridian (International Celestial Reference Frame) | ≈ 86 164.1 s |
| دهه | dec | ≡ 10 a (see below for definition of year length) | = 10 years |
| fortnight | fn | ≡ 2 wk | = 1 209 600 s |
| helek |  | ≡ 1/1 080 h | = 3.۳ s |
| Hipparchic cycle |   | ≡ 4 Callippic cycles - 1 d | = 9.593 424‎×۱۰۹ s |
| ساعت (زمان) | h | ≡ 60 min | = 3 600 s |
| jiffy | j | ≡ 1/60 s | = .01۶ s |
| jiffy (alternate) | ja | ≡ 1/100 s | = 10 ms |
| ke (quarter of an hour) |   | ≡ ¼ h = 1/96 d | = 60 × 60 / 4 s = 900 s = 60 / 4 min = 15 min |
| ke (traditional) |   | ≡ 1/100 d | = 24 × 60 × 60 / 100 s = 864 s = 24 * 60 / 100 min = 14.4 min |
| lustre; lustrum |   | ≡ 5 a of 365 d | = 1.5768‎×۱۰۸ s |
| دوره متونی; enneadecaeteris |   | ≡ 110 mo (hollow) + 125 mo (full) = 6940 d ≈ 19 a | = 5.996 16‎×۱۰۸ s |
| هزاره |   | ≡ 1 000 a (see below for definition of year length) | = 1000 years |
| milliday | md | ≡ 1/1 000 d | = 24 × 60 × 60 / 1 000 s = 86.4 s |
| دقیقه | min | ≡ 60 s, due to ثانیه کبیسهs sometimes 59 s or 61 s, | = 60 s |
| moment |   | ≡ 90 s | = 90 s |
| ماه (زمان) (full) | mo | ≡ 30 d | = 2 592 000 s |
| ماه (زمان) (Greg. av.) | mo | Average Gregorian month = 1 a (Gregorian average) / 12 = 365.242 5 d / 12 = 30.436 875 d | ≈ 2.6297‎×۱۰۶ s |
| ماه (زمان) (hollow) | mo | ≡ 29 d | = 2 505 600 s |
| ماه (زمان) (synodic) | mo | Cycle time of moon phases ≈ 29.530 589 d (Average) | ≈ 2.551‎×۱۰۶ s |
| octaeteris |   | = 48 mo (full) + 48 mo (hollow) + 3 mo (full) = 8 a of 365.25 d = 2922 d | = 2.524 608‎×۱۰۸ s |
| زمان پلانک |   | ≡ (ثابت گرانشثابت پلانک/سرعت نور5)½ | ≈ 1.351 211 868‎×۱۰−۴۳ s |
| ثانیه | s | time of 9 192 631 770 periods of the radiation corresponding to the transition between the 2 hyperfine levels of the ground state of the caesium 133 atom at 0 K (but other seconds are sometimes used in astronomy) | (یکای اصلی اس‌آی) |
| shake |   | ≡ 10−8 s | = 10 ns |
| sigma |   | ≡ 10−6 s | = 1 μs |
| Sothic cycle |   | ≡ 1 461 a of 365 d | = 4.607 4096‎×۱۰۱۰ s |
| svedberg | S | ≡ 10−13 s | = 100 fs |
| هفته | wk | ≡ 7 d | =  168 h = 10 080 min = 604 800 s |
| سال (Gregorian) | a, y, or yr | = 365.2425 d average, calculated from common years (365 d) plus leap years (366 d) on most years divisible by 4. See سال کبیسه for details. | = 31 556 952 s |
| year (Julian) | a, y, or yr | = 365.25 d average, calculated from common years (365 d) plus one leap year (366 d) every four years | = 31 557 600 s |
| سال نجومی (sidereal) | a, y, or yr | ≡ time taken for Sun to return to the same position with respect to the stars of the celestial sphere | ≈ 365.256 363 d ≈ 31 558 149.7632 s |
| سال اعتدالی (tropical) | a, y, or yr | ≡ Length of time it takes for the Sun to return to the same position in the cycle of seasons | ≈ 365.242 190 d ≈ 31 556 925 s |
Where ساعت هماهنگ جهانی is observed, the length of time units longer than 1 s may increase or decrease by 1 s if a ثانیه کبیسه occurs during the time interval of interest.: Where ساعت هماهنگ جهانی is observed, the length of time units longer than 1 s may increase or decrease by 1 s if a ثانیه کبیسه occurs during the time interval of interest.