Days (d)
The day is a unit of time equal to 24 hours or 86,400 seconds, based on one rotation of the Earth relative to the Sun.
Convert days to any time unit
1 day = 24 hours
Quick facts
- Unit
- Day (plural: days)
- Symbol
- d
- Measures
- Time / Duration
- System
- Everyday
- Equals
- 86,400 seconds
- Definition
- 24 hours, 86,400 seconds.
1 day in other units
| Hours | 24 h |
| Minutes | 1,440 min |
| Seconds | 86,400 s |
| Years | 0.002737907007 yr |
| Months | 0.03285488408 mo |
| Weeks | 0.1428571429 wk |
| Milliseconds | 86,400,000 ms |
| Centuries | 0.00002737907 c |
What is a day?
The day is a unit of time equal to 24 hours or 86,400 seconds, based on one rotation of the Earth relative to the Sun. It is accepted for use with the SI. The actual solar day varies by a few milliseconds because the Earth's rotation is not perfectly regular.
Where the day sits among time units
The day is number 41 of 101 on our scale of time units, ordered from smallest to largest.
What days are used for
- Calendars, schedules and deadlines
- Interest calculations and contracts
- Medicine (doses per day)
Days in real life
- A week has 7 days
- A common year has 365 days
- The Moon takes about 27.3 days to orbit the Earth
One day is about 3 working days, or about 3 transatlantic flights, or about 12 elite marathons, or about 12 feature films.
Top day conversions
Common amounts of days
- 0.1 d
- 0.2 d
- 0.3 d
- 0.4 d
- 0.5 d
- 0.6 d
- 0.7 d
- 0.8 d
- 0.9 d
- 1 d
- 1.5 d
- 2 d
- 2.5 d
- 3 d
- 3.5 d
- 4 d
- 4.5 d
- 5 d
- 6 d
- 7 d
- 7.5 d
- 8 d
- 9 d
- 10 d
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- 700 d
- 800 d
- 900 d
- 1,000 d
- 1,200 d
- 1,500 d
- 2,000 d
- 2,500 d
- 3,000 d
- 4,000 d
- 5,000 d
- 10,000 d
Convert days to all 100 other units
Everyday
- d to h
- d to min
- d to s
- d to yr
- d to mo
- d to wk
- d to c
- d to dec
- d to ka
- d to fn
- d to Q
- d to common year
- d to leap year
- d to semester
- d to 30-day month
- d to score (20 years)
Metric (SI)
Astronomical
- d to a
- d to sidereal day
- d to synodic month
- d to tropical year
- d to Ma
- d to sidereal year
- d to Mars sol
- d to galactic year
- d to Ga
- d to sidereal month
- d to saros
- d to Mars year
- d to Metonic cycle
- d to Platonic year
- d to anomalistic year
- d to draconic year
- d to Jupiter day
- d to Sothic cycle
- d to Venus day
- d to anomalistic month
- d to draconic month
- d to Callippic cycle
- d to Gaussian year
- d to Hipparchic cycle
- d to Pluto year
- d to sidereal second
- d to tropical month
Scientific
Historical & cultural
- d to generation
- d to olympiad
- d to baktun
- d to decimal hour
- d to 刻
- d to 时辰
- d to .beat
- d to decimal minute
- d to decimal second
- d to ghati
- d to jubilee
- d to kalpa
- d to lustrum
- d to moment (medieval)
- d to muhurta
- d to yuga
- d to cd
- d to 更
- d to helek
- d to indiction
- d to kalabtun
- d to katun
- d to kin (Maya)
- d to mahayuga
- d to manvantara
- d to piktun
- d to triennium
- d to tun (Maya)
- d to vighati
- d to winal
Everyday comparisons
Convert to days
Frequently asked questions
What is a day?
The day is a unit of time equal to 24 hours or 86,400 seconds, based on one rotation of the Earth relative to the Sun.
How is the day defined?
24 hours, 86,400 seconds.
How many hours are in a day?
One day equals 24 hours.
How many minutes are in a day?
One day equals 1,440 minutes.
How many seconds are in a day?
One day equals 86,400 seconds.