Conversion formula

The conversion factor from days to hours is 24, which means that 1 day is equal to 24 hours:

1 d = 24 hr

To convert 21 days into hours we have to multiply 21 by the conversion factor in order to get the time amount from days to hours. We can also form a simple proportion to calculate the result:

1 d → 24 hr

21 d → T_(hr)

Solve the above proportion to obtain the time T in hours:

T_(hr) = 21 d × 24 hr

T_(hr) = 504 hr

The final result is:

21 d → 504 hr

We conclude that 21 days is equivalent to 504 hours:

21 days = 504 hours

Alternative conversion

We can also convert by utilizing the inverse value of the conversion factor. In this case 1 hour is equal to 0.001984126984127 × 21 days.

Another way is saying that 21 days is equal to 1 ÷ 0.001984126984127 hours.

Approximate result

For practical purposes we can round our final result to an approximate numerical value. We can say that twenty-one days is approximately five hundred four hours:

21 d ≅ 504 hr

An alternative is also that one hour is approximately zero point zero zero two times twenty-one days.

Conversion table

days to hours chart

For quick reference purposes, below is the conversion table you can use to convert from days to hours