Convert Angle from arcminutes to arcseconds (arcmin to arcsec)

arcminute to arcsecond Conversion Formula

Example

Let's convert 5 arcminute (arcmin) to arcsecond (arcsec).

Using the formula:

Therefore, 5 arcminute (arcmin) is equal to 300 arcsecond (arcsec).

How many arcminutes are in one arcsecond? One arcsecond (arcsec) contains 0.016666666666666666667 arcminutes (arcmin) — the inverse of the factor above. Multiplying by 60 takes you from arcminutes to arcseconds; multiplying by 0.016666666666666666667 brings you back.

Put in words: one arcminute equals 60 arcseconds, so the arcminute is the larger unit of this pair. Converting between them never changes the amount of angle being measured — only the size of the unit you count it in.

What Is an Arcminute (arcmin)?

An arcminute (plural: arcminutes) is a precise unit of angular measurement, equal to 1/60th of a degree.

It provides a way to measure very small angles with high accuracy and is frequently used in scientific and technical fields. The common abbreviation for arcminute is arcmin.

How Many Arcminutes Are in a Degree?

There are precisely 60 arcminutes within a single degree.

This relationship is a core part of the "degrees, minutes, seconds" (DMS) system of measurement, which breaks down angles into smaller parts for greater precision.

• 1 degree (°) = 60 arcminutes (′)

What Is the Symbol for an Arcminute?

The universally recognized symbol for an arcminute is the prime symbol (′).

This symbol is placed directly after the number to denote the measurement. For example, an angle of 45 and a half degrees can be expressed as 45° 30′.

What Are Arcminutes Used For?

Arcminutes are essential in fields that demand precise angular resolution. Key applications include:

• Astronomy: Astronomers use arcminutes to measure the apparent size of celestial objects as seen from Earth and the distance between them in the sky.

• Navigation: In celestial navigation and cartography, one arcminute of latitude along any meridian on the Earth's surface is approximately equal to one nautical mile.

• Surveying: Surveyors use arcminutes to measure land boundaries and features over long distances accurately.

The Arcminute in Human Vision

The arcminute is the unit in which normal eyesight is defined.

"20/20 vision" means that at 20 feet you can resolve detail subtending one arcminute of visual angle. On a Snellen eye chart, each stroke of a letter on the 20/20 line — and each gap in it — is exactly one arcminute wide as seen from the testing distance; the whole letter spans five. That is not an arbitrary benchmark: it is close to the physical resolution limit set by the spacing of cone cells in the fovea.

The same unit explains a familiar rule of thumb in the sky. The Sun and the full Moon each span about 30 arcminutes — half a degree — which is why a total solar eclipse works at all, and why the Moon photographs so much smaller than it appears.

Arcminutes in Shooting and Optics

In marksmanship the arcminute travels under the abbreviation MOA (minute of angle), and it is used because angular error scales linearly with distance.

One arcminute subtends almost exactly 1.047 inches at 100 yards, which shooters round to one inch. That approximation makes the arithmetic trivial: 1 MOA covers roughly 1 inch at 100 yards, 2 inches at 200 yards, 5 inches at 500 yards. A rifle described as "sub-MOA" groups its shots inside about an inch at 100 yards.

Rifle scopes inherit the unit directly — adjustment turrets typically move the point of impact by 1/4 MOA per click, or about a quarter inch at 100 yards. The metric alternative, the milliradian, divides a radian into thousandths instead, giving 10 cm at 100 m per mil; 1 mil is about 3.44 MOA.

What Is an Arcsecond (arcsec)?

An arcsecond (arcsec) is a tiny unit of angular measurement, equal to 1/3600th of a degree.

To put that in perspective, one arcsecond is roughly the angular size of a dime viewed from over a mile away. As a unit in the International System of Units (SI), it's essential for measuring extremely small angles with high precision.

How Do Astronomers Use Arcseconds?

Arcseconds are fundamental in astronomy for measuring the apparent size and separation of celestial objects as seen from Earth.

Because stars and galaxies are so distant, their angular size in the sky is incredibly small. Astronomers use arcseconds to precisely quantify the separation between double stars, the diameter of distant galaxies, and the intricate details of nebulae.

This level of precision is also critical for calculating stellar parallax. This is a method used to determine the distances to nearby stars by measuring their slight shift in position against a distant background as the Earth orbits the Sun over six months.

How Are Arcseconds and Parsecs Related?

The arcsecond is directly used to define the parsec (pc), a primary unit for measuring astronomical distances.

A parsec is defined as the distance at which a star would have a parallax angle of exactly one arcsecond. In other words, if an object is one parsec away, it will appear to shift by one arcsecond in the sky as the Earth moves from one side of its orbit to the other.

This direct relationship makes the arcsecond indispensable for building the cosmic distance ladder and mapping the vastness of space.

Everyday Uses for Arcseconds: GPS and Maps

Beyond the cosmos, arcseconds are crucial for high-precision geography, cartography, and navigation right here on Earth.

Latitude and longitude coordinates are expressed in degrees, minutes, and arcseconds. One arcsecond of latitude corresponds to a nearly constant distance of about 30.92 meters (101.4 feet) on the Earth's surface.

This allows for the highly accurate location pinpointing that is essential for modern GPS systems, land surveying, aviation, and any application requiring precise geographic positioning.

arcminute to arcsecond Conversion Table

Here are some quick reference conversions from arcminute (arcmin) to arcsecond (arcsec):