ScientificConverters.com Precise unit conversions for science & engineering.

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    Convert Days to Hours

    1 day (d) equals 24 hours (h).

    d
    Swap: convert hours to days
    h

    1 d = 24 h

    Type in either box. Scientific notation works: 1.5e-3.

    Converting a list? Use the bulk day to hour converter to paste a column from Excel.

    How to Convert Day to Hour

    • 1 d = 24 h
    • 1 h = 0.04166666667 d
    • Example: convert 15 d to h: 15 d = 15 × 24 h = 360 h

    Formula

    h = d × 24

    Derivation from SI units:

    • 1 d = 24 h = 86 400 s
    • 1 h = 60 min = 3600 s
    • 1 d = 86400 s ÷ 3600 s per h = 24 h

    Both units are defined exactly, so the factor is exact. Day definition: day; Hour definition: hour.

    Worked examples

    1. A 7 d stability test runs for 168 h.
      7 d × 24 = 168 h
    2. 1.5 d equals 36 h.
      1.5 d × 24 = 36 h

    Day to Hour conversion table

    Day to Hour conversion table
    Days (d)Hours (h)
    0.5 d12 h
    1 d24 h
    2 d48 h
    3 d72 h
    5 d120 h
    7 d168 h
    10 d240 h
    14 d336 h
    15 d360 h
    21 d504 h
    28 d672 h
    30 d720 h
    31 d744 h
    45 d1080 h
    60 d1440 h
    90 d2160 h
    100 d2400 h
    180 d4320 h
    365 d8760 h
    366 d8784 h
    1000 d24000 h

    Where it's used

    Converting days to hours is needed for incubation, curing and burn-in times that are specified in days but logged by hour meters.

    Day to other time units

    1 d expressed in every time unit
    Conversion1 d equals
    day to millisecond 86400000 ms
    day to second 86400 s
    day to minute 1440 min
    day to hour 24 h

    Frequently asked questions

    How many hours are in 30 days?

    30 d = 720 h.

    How many hours are in 1 day?

    1 d = 24 h.

    How do I convert days to hours?

    Multiply the value in d by 24. For example, 15 d × 24 = 360 h.

    Is the d to h conversion exact?

    Yes. Both units are defined exactly, and 1 d is exactly 24 h.

    Sources

    Last reviewed: . Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.

    Cite this page

    APA

    Scientific Converters. (2026, October 15). Convert Days to Hours. Retrieved October 17, 2026, from https://scientificconverters.com/time/days-to-hours/

    IEEE

    Scientific Converters, "Convert Days to Hours," scientificconverters.com. Accessed: Oct. 17, 2026. [Online]. Available: https://scientificconverters.com/time/days-to-hours/