Tropical Year to Sidereal Day Converter

Time Converter

21 units available

Decimals:

From

To

366.24219

1 trop yr = 366.24219 sid day

Formula:

sid day = trop yr × 366.2421901384

With your value: 1 trop yr = 366.24219014 sid day

How big is that?

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

Minute (1/5.3e+5 your value)0.00000190 trop yr

Working day (1/1.1e+3 your value)0.000913 trop yr

Day (1/3.7e+2 your value)0.00274 trop yr

Week (1/52 your value)0.0192 trop yr

Your value1.00 trop yr

Year (1.0× your value)1.00 trop yr

Other Tropical Year to Sidereal Day conversions

2 trop yr to sid day 3 trop yr to sid day 4 trop yr to sid day 5 trop yr to sid day 6 trop yr to sid day 7 trop yr to sid day 8 trop yr to sid day

Tropical Year to Sidereal Day Conversion Table

Tropical Year (trop yr)	Sidereal Day (sid day)
0.5	183.121095
1	366.24219
2	732.48438
5	1,831.210951
10	3,662.421901
15	5,493.632852
20	7,324.843803
25	9,156.054753
50	18,312.109507
100	36,624.219014
250	91,560.547535
500	183,121.095069
1000	366,242.190138

Sidereal Day to Tropical Year Conversion Table

Sidereal Day (sid day)	Tropical Year (trop yr)
0.5	0.001365
1	0.00273
2	0.005461
5	0.013652
10	0.027304
15	0.040957
20	0.054609
25	0.068261
50	0.136522
100	0.273043
250	0.682608
500	1.365217
1000	2.730434

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.

Tropical Year (trop yr)

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

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

How to Convert Tropical Year to Sidereal Day

To convert from Tropical Year (trop yr) to Sidereal Day (sid day), multiply the value by 366.2421901384.

Formula: sid day = trop yr × 366.2421901384

Reverse: trop yr = sid day × 0.0027304336

Step-by-Step Example

Start with your value in Tropical Year. For example: 5 trop yr
Multiply by the conversion factor: 5 x 366.2421901384
The result is: 1,831.210951 sid day

About Tropical Year

The tropical year (trop yr) is a unit of time. One tropical year equals 3.155693 × 10^+7 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 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.

Frequently Asked Questions

How many Sidereal Day are in 1 Tropical Year?

There are exactly 366.2421901384 Sidereal Day in 1 Tropical Year. This means the conversion factor from Tropical Year to Sidereal Day is 366.2421901384.

What is the formula to convert Tropical Year to Sidereal Day?

The formula to convert Tropical Year to Sidereal Day is: sid day = trop yr × 366.2421901384. For example, to convert 10 Tropical Year to Sidereal Day, you would multiply 10 by 366.2421901384.

What is a Tropical Year?