How do I convert days to hours?

Multiply the day value by 24. So x d × 24 = the equivalent in h.

How do I convert back from hours to days?

Multiply the hour value by 0.0416667. For example, 1 h = 0.0416667 d.

Is the day bigger than the hour?

Yes. 1 day is larger than 1 hour — specifically 24 times larger.

Are these conversion factors exact?

Yes. The factor of 24 is derived directly from the SI definitions of day and hour.

Days to Hours Converter

1 d = 24 h (day → hour)

1 d = 24 h

1 day equals 24 hours. To convert days to hours, multiply the day value by 24. For quick reference: 1 d = 24 h, 5 d = 120 h, 10 d = 240 h, 100 d = 2400 h.

From

FormulaHours = Days × 24

Quick

When to use days → hours

Days to hours multiplies by 24. A 3-day weekend is 72 hours; a 14-day notice period is 336 hours. Used in pricing models (hourly car rentals quoted from a daily rate), shift-planning (3-shift coverage = 24 hours = 1 day), and SLA contracts ("99.9 % uptime" = 8.76 hours of allowed downtime per year = 0.365 days). Daylight saving transitions can make one day 23 or 25 hours; engineering scheduling typically uses UTC days to avoid this.

How to convert days to hours

Take your value
Start with your value in days.
Multiply by 24
Multiply the day value by 24. This is the exact conversion factor from days to hours.
Read the result
The product is your value in hours. For example, 5 d × 24 = 120 h.

Conversion formula

The exact factor from days to hours is 24.

Hours = Days × 24

Days to Hours conversion table

Fifty common reference values, hand-picked for skim utility. Use the calculator above for any value not listed.

Conversion table from days to hours
Days (d)	Hours (h)
1 d	24 h
2 d	48 h
3 d	72 h
4 d	96 h
5 d	120 h
6 d	144 h
7 d	168 h
8 d	192 h
9 d	216 h
10 d	240 h
15 d	360 h
20 d	480 h
25 d	600 h
30 d	720 h
45 d	1080 h
60 d	1440 h
90 d	2160 h
100 d	2400 h
120 d	2880 h
150 d	3600 h
180 d	4320 h
240 d	5760 h
300 d	7200 h
360 d	8640 h
450 d	10800 h
500 d	12000 h
600 d	14400 h
750 d	18000 h
900 d	21600 h
1000 d	24000 h
1200 d	28800 h
1500 d	36000 h
1800 d	43200 h
2400 d	57600 h
3000 d	72000 h
3600 d	86400 h
4500 d	108000 h
6000 d	144000 h
7200 d	172800 h
9000 d	216000 h
10000 d	240000 h
18000 d	432000 h
36000 d	864000 h
43200 d	1036800 h
86400 d	2073600 h
172800 d	4147200 h
604800 d	14515200 h
1000000 d	24000000 h
31557600 d	757382400 h
100000000 d	2400000000 h

Real-world reference

One Earth rotation is 1 d. A standard rental period is often 1 d. In hours, that gives you: 1 d = 24 h, 10 d = 240 h, 100 d = 2400 h.

Frequently asked questions

How many hours are in 1 day?: 1 day equals 24 hours.
How do I convert days to hours?: Multiply the day value by 24. So x d × 24 = the equivalent in h.
What is 5 days in hours?: 5 days equals 120 hours.
What is 10 days in hours?: 10 days equals 240 hours.
What is 100 days in hours?: 100 days equals 2400 hours.
How do I convert back from hours to days?: Multiply the hour value by 0.0416667. For example, 1 h = 0.0416667 d.
Is the day bigger than the hour?: Yes. 1 day is larger than 1 hour — specifically 24 times larger.
Are these conversion factors exact?: Yes. The factor of 24 is derived directly from the SI definitions of day and hour.

About the day and the hour

The day

The day (d) equals exactly 86,400 seconds, or 24 hours. This is the conventional 'civil' day used in calendars and contracts. The actual solar day (one full rotation of Earth relative to the Sun) varies slightly throughout the year; the difference is reconciled in atomic time scales using leap seconds.

The hour

The hour (h) equals exactly 3,600 seconds, or 60 minutes. It is the standard unit for daily scheduling, employment, and short-distance travel time. Like the minute, it is accepted for use with the SI but is not strictly part of the SI system.