Angle Converter
Convert between degrees, radians, gradians, arcminutes, arcseconds, turns and milliradians. Use Basic, Advanced or Operations mode (add/subtract/normalize angles). Expressions like pi/6 or 180/7 are supported.
Reference: conversion factors
| Unit | Equivalent |
|---|---|
| 1 degree | π/180 rad ≈ 0.0174532925199433 rad |
| 1 radian | 180/π deg ≈ 57.2957795130823° |
| 1 grad (gon) | 0.9° = π/200 rad |
| 1 arcminute | 1/60° = 0.0166666667° |
| 1 arcsecond | 1/3600° ≈ 0.0002777778° |
| 1 turn | 360° = 2π rad |
| 1 milliradian (mrad) | 0.001 rad |
Angle Units, Conversion, and Practical Use — a guide
Angles are everywhere in mathematics, physics, engineering and everyday applications. Yet "angle" is not a single number — it comes in multiple units, each useful in different contexts. The most familiar is the degree: a full rotation equals 360 degrees, a convention inherited from ancient astronomy and division systems. Radians, by contrast, are the natural unit of angle in calculus and analytic mathematics: one radian measures the angle subtended by an arc equal in length to the circle's radius, and a full rotation is 2π radians. Gradians (also called gons), which divide a circle into 400 parts, are used in surveying and some civil engineering contexts. Beyond these are arcminutes and arcseconds (sexagesimal subdivisions of a degree), milliradians (small-angle approximations in ballistics and optics), and turns (a convenient unit where 1 turn = 360°).
Why multiple units?
Different units arise because they simplify different formulas or fit practical needs. Radians make trigonometric series, derivatives and integrals clean—e.g., d/dx (sin x) = cos x only if x is in radians. Degrees are intuitive and widely used in navigation, maps and everyday geometry. Gradians are convenient where decimal subdivisions of a right angle (100 grads) are preferred, such as in some surveying instruments. Arcminutes and arcseconds are common in astronomy, geodesy and mapping, where angular precision beyond a degree is important. Milliradians are used in targeting systems and ballistics because small angles in radians approximate linear offsets via simple multiplication (≈ distance × angle in radians).
Core conversion formulas
The conversion formulas are exact and simple:
- radians = degrees × π / 180
- degrees = radians × 180 / π
- gradians = degrees × 10/9
- arcminutes = degrees × 60
- arcseconds = degrees × 3600
- turns = degrees / 360 (or radians / 2π)
- milliradians = radians × 1000
Because these relations are linear, converting between any two units can be done by composing conversions through a common base (commonly degrees or radians). The Angle Converter implements these formulas precisely and presents step-by-step explanations to help you understand the computation.
Expressions and parsing
Modern workflows often require entering expressions rather than single numbers. For example, specifying π/6 for 30 degrees or a radian expression for analytic work. The converter accepts simple expressions such as pi/3, 2*pi, 180/7, and sqrt(2) for numeric evaluation. Expressions are parsed and evaluated with safety checks; invalid expressions produce clear error messages describing allowed syntax.
Advanced units: arcminutes / arcseconds
Arcminutes (') and arcseconds (\") split degrees into finer units. One arcminute equals 1/60 of a degree and one arcsecond equals 1/60 of an arcminute (1/3600 of a degree). These units are central in astronomy: the apparent size of objects on the sky is commonly given in arcseconds. The Angle Converter converts to and from these units and provides sexagesimal representations when helpful.
Angle arithmetic and normalization
Adding and subtracting angles is straightforward in numeric terms, but often a result must be normalized: for instance, mapping a rotation measure into [0°, 360°) or into (−180°, 180°] depending on your convention. Normalization is useful in robotics, navigation and animation. The Operations mode lets you add/subtract a list of angles (entered in mixed units), compute the numeric total, and normalize according to common choices. The tool shows intermediate values (converted into a common base) and the final normalized output.
Practical examples
- Convert 45° to radians: radians = 45 × π / 180 = π/4 ≈ 0.7853981634.
- Convert 2π/3 radians to degrees: degrees = 2π/3 × 180/π = 120°.
- Add angles: add 30° + pi/6 rad + 50 grad — the tool converts each to a common unit, sums, and returns normalized result in your chosen unit.
Accuracy and floating-point care
Conversions use double-precision arithmetic (IEEE 754) internally. That is plenty for general engineering, mapping and educational use. When high-precision arithmetic is needed (e.g., certain geodetic computations), specialized libraries or symbolic tools are appropriate. This converter focuses on correctness, clarity and pedagogical step output for typical classroom and engineering tasks.
Visualization
To help intuition, the page includes a small diagram relating degrees, radians and gradians on a circular dial; this visualizes that 360° = 2π rad = 400 grad. Visual cues aid comprehension when working across unit systems.
Using the Angle Converter effectively
- Pick the appropriate mode: Basic for quick conversions, Advanced to include arcminutes or milliradians, and Operations for arithmetic and normalization.
- Enter expressions like
pi/4or180/7directly in input fields when that is convenient. - Enable steps to see how the conversion was performed; export CSV when you need to retain a record of calculations.
Conclusion
Understanding and converting angle units reliably is a small but essential skill across many fields. The Angle Converter gives you a convenient, accurate and educational interface to convert, combine and normalize angles — supporting everything from classroom homework to quick engineering checks.
Frequently Asked Questions
Yes — use 'pi' or 'π' and arithmetic (e.g., pi/6). The parser supports sqrt(...) and basic operators.
Normalize to [0°,360°) or (−180°,180°], or choose no normalization in Operations mode.
Yes — milliradians are convenient for small-angle linear approximations, used in optics and ballistics.
Yes — 1 arcsecond = 1/3600 degree. Use Advanced mode to convert.
Conversions are computed with double precision; for extremely high-precision use specialized libraries.
The calculator will show an error and an example of allowed formats (pi, sqrt(), arithmetic, parentheses).
Yes — list each angle on its own line with a unit in Operations mode, and the tool will sum them correctly.
Yes — gradians are still used in surveying and some civil engineering tools; they divide the circle into 400 grads.
Yes — copy results to clipboard or download CSV containing inputs, outputs and step explanations.
Yes — enable the "Show steps" checkbox in each mode to display the formulas and intermediate values used.