How many hours are in 1 day?

1 d equals 24 h. This is an exact conversion factor defined by NIST.

How do I convert days to hours?

Multiply the value in d by the conversion factor. For example, 10 d = 240 h. Use our calculator above for instant results.

Is the days to hours conversion exact?

Yes, this conversion is mathematically exact based on the international definition of these units (NIST SP 811).

Can I convert days to hours offline?

Yes! OmniConvert runs entirely in your browser — no internet connection needed after the page loads. Your data never leaves your device, ensuring complete privacy.

What is the difference between days and hours?

Days (d) and Hours (h) are both units of time but belong to different measurement systems. 1 d = 24 h. Use the converter above to switch between them instantly.

Days to Hours (d → h) — Free Online Converter

d → h Reference Table

d	h
0.001 d	0.024 h
0.002 d	0.048 h
0.003 d	0.072 h
0.004 d	0.096 h
0.005 d	0.12 h
0.006 d	0.144 h
0.007 d	0.168 h
0.008 d	0.192 h
0.009 d	0.216 h
0.01 d	0.24 h
0.02 d	0.48 h
0.03 d	0.72 h
0.04 d	0.96 h
0.05 d	1.2 h
0.06 d	1.44 h
0.07 d	1.68 h
0.08 d	1.92 h
0.09 d	2.16 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
5.5 d	132 h
6 d	144 h
6.5 d	156 h
7 d	168 h
7.5 d	180 h
8 d	192 h
8.5 d	204 h
9 d	216 h
9.5 d	228 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
25 d	600 h
30 d	720 h
35 d	840 h
40 d	960 h
45 d	1080 h
50 d	1200 h
55 d	1320 h
60 d	1440 h
65 d	1560 h
70 d	1680 h
75 d	1800 h
80 d	1920 h
85 d	2040 h
90 d	2160 h
95 d	2280 h
100 d	2400 h
120 d	2880 h
125 d	3000 h
130 d	3120 h
140 d	3360 h
150 d	3600 h
160 d	3840 h
175 d	4200 h
180 d	4320 h
200 d	4800 h
225 d	5400 h
250 d	6000 h
275 d	6600 h
300 d	7200 h
350 d	8400 h
400 d	9600 h
450 d	10800 h
500 d	12000 h
600 d	14400 h
700 d	16800 h
750 d	18000 h
800 d	19200 h
900 d	21600 h
1000 d	24000 h
1200 d	28800 h
1250 d	30000 h
1500 d	36000 h
1750 d	42000 h
2000 d	48000 h
2500 d	60000 h
3000 d	72000 h
4000 d	96000 h
4500 d	108000 h
5000 d	120000 h
6000 d	144000 h
7000 d	168000 h
7500 d	180000 h
8000 d	192000 h
9000 d	216000 h
10000 d	240000 h
15000 d	360000 h
20000 d	480000 h
25000 d	600000 h
50000 d	1200000 h
75000 d	1800000 h
100000 d	2400000 h

Values based on NIST SP 811 conversion factors

Why Convert Days to Hours?

Converting between days (d) and hours (h) is one of the most common time conversions. Whether for engineering, cooking, travel, or science, knowing how to quickly convert d to h saves time and prevents errors.

Time conversion between d and h is essential for project management, astronomy, and high-speed electronics. While day-to-day scheduling is simple, scientific and engineering fields often require converting between vast timescales (millennia) and infinitesimal ones (nanoseconds). Video editors and audio engineers work with frames and samples that require precise time unit conversions to sync media perfectly. In logistics, accurate delivery estimates depend on converting travel durations across time zones and varying speed metrics. Miscalculating time units can lead to missed deadlines, data desynchronization, or navigation errors in GPS systems.

How to Convert Days to Hours

To convert days to hours, use the following formula:

h = d × 24

Example: 1 d = 24 h

For example, 5 d = 120 h, 10 d = 240 h, and 100 d = 2400 h. For larger values, 1000 d = 24000 h. Conversely, 1 h = 0.04166666667 d. Our calculator above performs this conversion instantly with full precision — no rounding errors.

Common Use Cases

One full day: 1 d = 24 h
One week: 7 d = 168 h
A typical weekend getaway: 3 d = 72 h
A standard two-week vacation: 14 d = 336 h
One year: 365 d = 8760 h

Common Mistakes to Avoid

Decimal time: thinking 1.50 hours is 1 hour 50 minutes (it's 1 hour 30 minutes).
Leap years: assuming every year has 365 days.
Month length: assuming all months are 30 days.

Pro Tips

Excel format: Be careful converting time in Excel; it stores dates as serial numbers.
Time zones: Always specify UTC offset when scheduling international calls.
Seconds in day: There are 86,400 seconds in a standard day.

What is a Day?

A unit of time based on Earth's rotation, equal to 24 hours.

Basic unit for daily life and calendars.

What is a Hour?

The hour (h) is a unit of time equal to 60 minutes or 3,600 seconds. Historically defined as 1/24 of a day.

Hours are the standard unit for work shifts, travel duration, and daily scheduling worldwide.

Days → Hours

Days to Hours Formula