How do I convert days to seconds?

Multiply the day value by 86400. So x d × 86400 = the equivalent in s.

What is 100 days in seconds?

100 days equals 8640000 seconds.

How do I convert back from seconds to days?

Multiply the second value by 1.1574 × 10^−5. For example, 1 s = 1.1574 × 10^−5 d.

Is the day bigger than the second?

Yes. 1 day is larger than 1 second — specifically 86400 times larger.

Are these conversion factors exact?

Yes. The factor of 86400 is derived directly from the SI definitions of day and second.

Days to Seconds Converter

1 d = 86400 s

1 day equals 86400 seconds. To convert days to seconds, multiply the day value by 86400. For quick reference: 1 d = 86400 s, 5 d = 432000 s, 10 d = 864000 s, 100 d = 8640000 s.

From

86400

FormulaSeconds = Days × 86400

Quick

How to convert days to seconds

Take your value
Start with your value in days.
Multiply by 86400
Multiply the day value by 86400. This is the exact conversion factor from days to seconds.
Read the result
The product is your value in seconds. For example, 5 d × 86400 = 432000 s.

Conversion formula

The exact factor from days to seconds is 86400.

Seconds = Days × 86400

Days to Seconds 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 seconds
Days (d)	Seconds (s)
1 d	86400 s
2 d	172800 s
3 d	259200 s
4 d	345600 s
5 d	432000 s
6 d	518400 s
7 d	604800 s
8 d	691200 s
9 d	777600 s
10 d	864000 s
15 d	1296000 s
20 d	1728000 s
25 d	2160000 s
30 d	2592000 s
45 d	3888000 s
60 d	5184000 s
90 d	7776000 s
100 d	8640000 s
120 d	10368000 s
150 d	12960000 s
180 d	15552000 s
240 d	20736000 s
300 d	25920000 s
360 d	31104000 s
450 d	38880000 s
500 d	43200000 s
600 d	51840000 s
750 d	64800000 s
900 d	77760000 s
1000 d	86400000 s
1200 d	103680000 s
1500 d	129600000 s
1800 d	155520000 s
2400 d	207360000 s
3000 d	259200000 s
3600 d	311040000 s
4500 d	388800000 s
6000 d	518400000 s
7200 d	622080000 s
9000 d	777600000 s
10000 d	864000000 s
18000 d	1555200000 s
36000 d	3110400000 s
43200 d	3732480000 s
86400 d	7464960000 s
172800 d	14929920000 s
604800 d	52254720000 s
1000000 d	86400000000 s
31557600 d	2726576640000 s
100000000 d	8640000000000 s

Real-world reference

One Earth rotation is 1 d. A standard rental period is often 1 d. In seconds, that gives you: 1 d = 86400 s, 10 d = 864000 s, 100 d = 8640000 s.

Frequently asked questions

How many seconds are in 1 day?: 1 day equals 86400 seconds.
How do I convert days to seconds?: Multiply the day value by 86400. So x d × 86400 = the equivalent in s.
What is 5 days in seconds?: 5 days equals 432000 seconds.
What is 10 days in seconds?: 10 days equals 864000 seconds.
What is 100 days in seconds?: 100 days equals 8640000 seconds.
How do I convert back from seconds to days?: Multiply the second value by 1.1574 × 10^−5. For example, 1 s = 1.1574 × 10^−5 d.
Is the day bigger than the second?: Yes. 1 day is larger than 1 second — specifically 86400 times larger.
Are these conversion factors exact?: Yes. The factor of 86400 is derived directly from the SI definitions of day and second.

About the day and the second

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 second

The second (s) is the SI base unit of time. It has been defined since 1967 in terms of the cesium-133 atomic transition, specifically as 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom.