Days to Hours Converter

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

Quick answer

One day is 24 hours: multiply days by 24. 3 days = 72 hours.

  • 1 day = 24 hours
  • 1 hour = 0.04166666667 days
  • Formula: h = d × 24
  • Quick estimate: multiply by 24: 7 days = 168 hours.

1 day = 24 hours

How to convert days to hours

h = d × 24

To convert days to hours, multiply the number of days by 24.

Example: 42 d to h

  1. Start with the value in days: 42 d.
  2. Multiply by 24: 42 × 24 = 1,008.
  3. Result: 42 days = 1,008 hours.

Going the other way, 1 hour = 0.041666666667 days, so to convert hours back to days you divide by the same number. See hours to days.

Where the conversion factor comes from

The second is the SI base unit of time, defined by the cesium-133 atomic clock. 1 minute = 60 s, 1 hour = 60 min = 3,600 s, 1 day = 24 h = 86,400 s, 1 week = 7 days. The base-60 system comes from ancient Babylonian astronomy.

Mental math: d to h in your head

Multiply by 24 (×25 minus the number): 4 days → 100 − 4 = 96 h.

When you need to convert days to hours

  • Shipping and delivery windows.
  • Medication and fasting schedules.

Common mistakes

  • Forgetting daylight saving days (23 or 25 hours) for exact local-time calculations.

Everyday days in hours

ExampleDaysHours
Weekend2 d48 h
Week7 d168 h
Month (30 days)30 d720 h

Days to hours conversion table

Days (d)Hours (h)
0.1 d 2.4 h
0.2 d 4.8 h
0.3 d 7.2 h
0.4 d 9.6 h
0.5 d 12 h
0.6 d 14.4 h
0.7 d 16.8 h
0.8 d 19.2 h
0.9 d 21.6 h
1 d 24 h
1.5 d 36 h
2 d 48 h
2.5 d 60 h
3 d 72 h
3.5 d 84 h
4 d 96 h
4.5 d 108 h
5 d 120 h
6 d 144 h
7 d 168 h
7.5 d 180 h
8 d 192 h
9 d 216 h
10 d 240 h
11 d 264 h
12 d 288 h
13 d 312 h
14 d 336 h
15 d 360 h
16 d 384 h
17 d 408 h
18 d 432 h
19 d 456 h
20 d 480 h
21 d 504 h
22 d 528 h
23 d 552 h
24 d 576 h
25 d 600 h
26 d 624 h

More d to h values

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.

More about days →

What is an hour?

The hour is a unit of time equal to 60 minutes or 3,600 seconds, one twenty-fourth of a day.

More about hours →

Convert days to other units

Convert other units to hours

Frequently asked questions

How many hours are in a day?

One day is 24 hours.

How many days are in an hour?

One hour is 0.04166666667 days.

What is the formula to convert days to hours?

h = d × 24.

How many hours in a week?

168 hours.