# Free online angle converter

> Angle measurement uses several unit systems. This converter handles all major angle units — degrees, radians, gradians, and more — with a full conversion table.

Convert between degrees, radians, gradians, turns, arcminutes, arcseconds, and NATO mils instantly.

**Interactive version:** https://onlinecalculator.me/unit-converters/angle/
**Category:** Unit Converters

## How to use

1. Enter a value.
2. Select the unit you are converting **from**.
3. Select the unit you want to convert **to**.
4. The result and full conversion table appear instantly.

## Supported units

| Unit | Symbol | Notes |
|------|--------|-------|
| Degrees | ° | Most common; 360° = full circle |
| Radians | rad | SI standard; 2π = full circle |
| Gradians | grad | 400 = full circle; used in surveying |
| Turns | — | 1 = full circle |
| Arcminutes | ′ | 1° = 60′ |
| Arcseconds | ″ | 1° = 3,600″ |
| NATO mils | mil | 6,400 = full circle |

## Key conversions

| From | To | Factor |
|------|----|--------|
| 1 degree | radians | π / 180 ≈ 0.017453 |
| 1 radian | degrees | 180 / π ≈ 57.2958 |
| 1 degree | gradians | 10/9 ≈ 1.1111 |
| 1 turn | degrees | 360 |
| 1 degree | arcminutes | 60 |
| 1 degree | arcseconds | 3,600 |

## Worked example

**180 degrees to radians:**

180° × (π / 180) = **π rad ≈ 3.14159 rad**

This is the most common conversion — a half-circle (180°) equals exactly π radians.

## Frequently asked questions

### What is a radian?

A radian is the angle subtended when the arc length equals the radius. One full circle = 2π radians ≈ 6.2832 rad. Radians are the SI standard unit for angles in mathematics and physics.

### What is the difference between degrees and gradians?

A full circle has 360 degrees or 400 gradians. Gradians (also called gon or grade) divide the right angle into 100 equal parts, making some surveying calculations simpler.

### What is a turn?

One turn is a full rotation (360°). It simplifies cyclic calculations — 0.25 turn = 90°, 0.5 turn = 180°, etc. Also called revolution or cycle.

### What are arcminutes and arcseconds?

One degree = 60 arcminutes (′). One arcminute = 60 arcseconds (″). These units are used in astronomy, GPS coordinates, and precise navigation.

### What are NATO mils?

NATO mils divide a full circle into 6,400 units. One degree ≈ 17.78 mils. Mils are used in artillery and military targeting because small angular changes translate predictably to distance changes at range.

## Sources

- [Angle and units of angular measurement](https://en.wikipedia.org/wiki/Angle) — Wikipedia
- [Radian (SI angle unit)](https://en.wikipedia.org/wiki/Radian) — Wikipedia

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