Sidereal Day to Second Converter

Time Converter

21 units available

Decimals:

From

To

86,164.0905

1 sid day = 86,164.0905 s

Formula:

s = sid day × 86,164.0905

With your value: 1 sid day = 86,164.0905 s

How big is that?

Everyday references on a logarithmic scale, all expressed in sidereal day so you can sanity-check the result.

Minute (1/1.4e+3 your value)0.000696 sid day

Working day (1/3.0 your value)0.334 sid day

Your value1.00 sid day

Day (1.0× your value)1.00 sid day

Week (7.0× your value)7.02 sid day

Year (3.7e+2× your value)366 sid day

Other Sidereal Day to Second conversions

2 sid day to s 3 sid day to s 4 sid day to s 5 sid day to s 6 sid day to s 7 sid day to s 8 sid day to s

Sidereal Day to Second Conversion Table

Sidereal Day (sid day)	Second (s)
0.5	43,082.04525
1	86,164.0905
2	172,328.181
5	430,820.4525
10	861,640.905
15	1,292,461.3575
20	1,723,281.81
25	2,154,102.2625
50	4,308,204.525
100	8,616,409.05
250	21,541,022.625
500	43,082,045.25
1000	86,164,090.5

Second to Sidereal Day Conversion Table

Second (s)	Sidereal Day (sid day)
0.5	5.802881e-6
1	1.160576e-5
2	2.321153e-5
5	5.802881e-5
10	0.000116
15	0.000174
20	0.000232
25	0.00029
50	0.00058
100	0.001161
250	0.002901
500	0.005803
1000	0.011606

Where these values come from

Every factor on this page is traced to the document that defines it. See the full provenance dataset or our methodology.

Sidereal Day (sid day)

Time

SI definition

Traceable to the second, defined by fixing the caesium-133 hyperfine transition frequency at 9 192 631 770 Hz.

Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)

Bureau International des Poids et Mesures · Reviewed 2026-07-01

Second (s)

Time

SI definition

The second is defined by taking the caesium-133 ground-state hyperfine transition frequency to be exactly 9 192 631 770 Hz.

Source: BIPM, The International System of Units (SI), 9th edition, 2019 (updated 2024)

Bureau International des Poids et Mesures · Reviewed 2026-07-01

How to Convert Sidereal Day to Second

To convert from Sidereal Day (sid day) to Second (s), multiply the value by 86,164.0905.

Formula: s = sid day × 86,164.0905

Reverse: sid day = s × 0.0000116058

Step-by-Step Example

Start with your value in Sidereal Day. For example: 5 sid day
Multiply by the conversion factor: 5 x 86,164.0905
The result is: 430,820.4525 s

About Sidereal Day

The sidereal day (sid day) is a unit of time. One sidereal day equals 86164.0905 seconds. UnitConvertLab converts it against every other time unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: time calculations, engineering and science, education.

About Second

The second (s) is a unit of time. One second equals 1 second. UnitConvertLab converts it against every other time unit using this exact definition, so results are reproducible to full double precision rather than rounded lookup tables.

Common uses: time calculations, engineering and science, education.

Frequently Asked Questions

How many Second are in 1 Sidereal Day?

There are exactly 86,164.0905 Second in 1 Sidereal Day. This means the conversion factor from Sidereal Day to Second is 86,164.0905.

What is the formula to convert Sidereal Day to Second?

The formula to convert Sidereal Day to Second is: s = sid day × 86,164.0905. For example, to convert 10 Sidereal Day to Second, you would multiply 10 by 86,164.0905.

What is a Sidereal Day?