Sidereal Day to Millisecond Converter

Time Converter

21 units available

Decimals:

From

To

86,164,090.5

1 sid day = 86,164,090.5 ms

Formula:

ms = sid day × 86,164,090.5

With your value: 1 sid day = 86,164,090.5 ms

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 Millisecond conversions

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

Sidereal Day to Millisecond Conversion Table

Sidereal Day (sid day)	Millisecond (ms)
0.5	43,082,045.25
1	86,164,090.5
2	172,328,181
5	430,820,452.5
10	861,640,905
15	1,292,461,357.5
20	1,723,281,810
25	2,154,102,262.5
50	4,308,204,525
100	8,616,409,050
250	21,541,022,625
500	43,082,045,250
1000	86,164,090,500

Millisecond to Sidereal Day Conversion Table

Millisecond (ms)	Sidereal Day (sid day)
0.5	5.802881e-9
1	1.160576e-8
2	2.321153e-8
5	5.802881e-8
10	1.160576e-7
15	1.740864e-7
20	2.321153e-7
25	2.901441e-7
50	5.802881e-7
100	1.160576e-6
250	2.901441e-6
500	5.802881e-6
1000	1.160576e-5

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

Millisecond (ms)

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

How to Convert Sidereal Day to Millisecond

To convert from Sidereal Day (sid day) to Millisecond (ms), multiply the value by 86,164,090.5.

Formula: ms = sid day × 86,164,090.5

Reverse: sid day = ms × 1.160576e-8

Step-by-Step Example

Start with your value in Sidereal Day. For example: 5 sid day
Multiply by the conversion factor: 5 x 86,164,090.5
The result is: 430,820,452.5 ms

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 Millisecond

The millisecond (ms) is a unit of time. One millisecond equals 0.001 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.

Frequently Asked Questions

How many Millisecond are in 1 Sidereal Day?

There are exactly 86,164,090.5 Millisecond in 1 Sidereal Day. This means the conversion factor from Sidereal Day to Millisecond is 86,164,090.5.

What is the formula to convert Sidereal Day to Millisecond?

The formula to convert Sidereal Day to Millisecond is: ms = sid day × 86,164,090.5. For example, to convert 10 Sidereal Day to Millisecond, you would multiply 10 by 86,164,090.5.

What is a Sidereal Day?