Convert Arcseconds to Milliradians
1 arcsecond is 0.004848 mrad. One arcsecond is exactly 0.0048481368111 milliradians.
One arcsecond is 0.0048481368 milliradians. To convert arcseconds to milliradians, multiply by 0.0048481368; to go the other way, divide by 0.0048481368 or multiply by 206.26481. The relation is exact but the figure is not: it is a rounding of a number that does not terminate, and it follows from NIST Special Publication 811. A 3,600th of a degree.
Factor checked against the defining standard · How we check
- Arcseconds × 0.0048481368
1 * 0.00484810.005 mrad
1 arcsecond in every angle unit
| Unit | Value | Exact factor |
|---|---|---|
| radians | 0.000004848136811 rad | × 0.0000048481368111 |
| degrees | 0.0002777777778 ° | × 0.000277777777778 |
| gradians | 0.0003086419753 gon | × 0.000308641975309 |
| arcminutes | 0.01666666667 ′ | × 0.0166666666667 |
| arcseconds (as entered) | 1 ″ | — |
| turns | 0.0000007716049383 turn | × 0.000000771604938272 |
| milliradians | 0.004848136811 mrad | × 0.0048481368111 |
Factors are entered by hand from NIST Special Publication 811 rather than derived from a units library, so the ones that terminate are exact rather than rounded.
How do you convert arcseconds to milliradians? The converter and the working
- 1.Take the measurement in arcseconds.
- 2.Multiply by 0.0048481368 — that is how many milliradians fit in one arcsecond.
- 3.To go back the other way, divide by 0.0048481368, or multiply by 206.26481.
Worked example: 25 arcseconds to milliradians
- Formula
- ″ × 0.0048481368 = mrad
- Arithmetic
- 25 × 0.0048481368 = 0.12 mrad
- Answer
- 25 ″ = 0.12 mrad
The factor is rounded for display; the figure above is computed from the full value.
Arcseconds to milliradians conversion table
| Arcseconds | Milliradians |
|---|---|
| 1 ″ | 0.004848 mrad |
| 2 ″ | 0.01 mrad |
| 3 ″ | 0.01 mrad |
| 4 ″ | 0.02 mrad |
| 5 ″ | 0.02 mrad |
| 6 ″ | 0.03 mrad |
| 7 ″ | 0.03 mrad |
| 8 ″ | 0.04 mrad |
| 9 ″ | 0.04 mrad |
| 10 ″ | 0.05 mrad |
| 12 ″ | 0.06 mrad |
| 15 ″ | 0.07 mrad |
| 20 ″ | 0.1 mrad |
| 25 ″ | 0.12 mrad |
| 50 ″ | 0.24 mrad |
| 100 ″ | 0.48 mrad |
| 200 ″ | 0.97 mrad |
| 300 ″ | 1.45 mrad |
| 500 ″ | 2.42 mrad |
| 1000 ″ | 4.85 mrad |
| 2000 ″ | 9.7 mrad |
| 5000 ″ | 24.24 mrad |
| 10000 ″ | 48.48 mrad |
What is an arcsecond?
A 3,600th of a degree. Stellar parallax is measured in these: a star one arcsecond of parallax away is one parsec from Earth, which is where the name comes from.
What is a milliradian?
A thousandth of a radian, and the unit rifle scopes adjust in: at 100 meters one milliradian moves the point of impact by 10 cm. The military "mil" is a different thing — 6,400 to a turn rather than the true 6,283.
How many milliradians are in an arcsecond?
One arcsecond is 0.0048481368 milliradians. Going the other way, one milliradian is 206.26481 arcseconds. Both figures come from the same defined relation rather than from a measurement, which is why they are the same today as they were in 1959.
Every angle unit here
The whole group — 7 units with their symbols and the size of each one in radians — is on the conversion index, along with every pair it makes. The table above already gives each of them relative to an arcsecond.
Source: NIST Special Publication 811 — the radian, and units accepted for use with the SI
Cite this page
- APA
- Rule Calculator. (2026). Convert Arcseconds to milliradians. Rule Calculator. https://rulecalculators.com/convert/arcsecond-to-milliradian
- MLA
- "Convert Arcseconds to milliradians." Rule Calculator, August 16, 2026, https://rulecalculators.com/convert/arcsecond-to-milliradian.
- Chicago
- Rule Calculator. "Convert Arcseconds to milliradians." Rule Calculator. Last reviewed August 16, 2026. https://rulecalculators.com/convert/arcsecond-to-milliradian.
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Questions people actually ask
- How many milliradians are in an arcsecond?
- 0.0048481368. A thousandth of a radian, and the unit rifle scopes adjust in: at 100 meters one milliradian moves the point of impact by 10 cm. The military "mil" is a different thing — 6,400 to a turn rather than the true 6,283.
- How do I convert milliradians back to arcseconds?
- Divide by 0.0048481368, or multiply by 206.26481 — they are the same operation.
Other angle conversions
Milliradians to arcseconds — the same conversion the other way.