Angle Converter
Convert between degrees, radians, and gradians.
How to use Angle Converter
Enter your angle value
Type your numeric angle value into the input field labeled 'Enter Angle'. You can use whole numbers (180) or decimals (45.5).
Select the input unit
Click the dropdown menu next to the input field and choose your current unit: Degrees (°), Radians (rad), or Gradians (gon).
Choose output units
Select which unit(s) you want to convert to using the checkboxes labeled 'Degrees', 'Radians', and 'Gradians' in the output section.
View instant results
Your converted values appear automatically in the results panel below. Copy any result using the copy icon next to each converted value.
How to Use Angle Converter Online — Free Guide (2026)
An angle converter is an essential tool for students, engineers, and professionals who work with angle measurements regularly. Whether you're converting degrees to radians for calculus homework or changing gradians for surveying projects, a free online angle converter saves time and eliminates manual calculation errors.
What Is an Angle Converter?
An angle converter instantly transforms angle measurements between three primary units: degrees (°), radians (rad), and gradians (gon). Degrees are the most common unit used in everyday applications, radians are essential for trigonometry and calculus, and gradians are preferred in surveying and military applications. This free online tool eliminates the need for calculators or memorizing conversion formulas.
How to Convert Degrees to Radians
Converting degrees to radians is straightforward with an online angle converter. First, enter your degree value (for example, 180) into the input field. Next, select 'Degrees' from the unit dropdown menu. Then, check the 'Radians' checkbox in the output section. Your result appears instantly—180 degrees equals π radians or approximately 3.14159 radians.
The mathematical formula is: Radians = Degrees × (π/180). For a 90-degree angle, multiply 90 × (π/180) to get π/2 radians or 1.5708 rad. This conversion is fundamental in trigonometry, calculus, and physics.
Converting Radians to Degrees
Reverting from radians to degrees follows the opposite process. Enter your radian value (such as 1.5708), select 'Radians' as your input unit, and check 'Degrees' in the output section. The converter displays the degree equivalent instantly.
The formula is: Degrees = Radians × (180/π). For example, π/2 radians × (180/π) = 90 degrees. This conversion helps when you need to express radian measurements in the more intuitive degree format.
Understanding Gradians
Gradians (also called gons or grades) divide a full circle into 400 units instead of 360 degrees. One gradian equals 0.9 degrees or π/200 radians. While less common than degrees or radians, gradians remain standard in surveying, mapping, and European engineering applications.
To convert 100 gradians to degrees: 100 × (360/400) = 90 degrees. The angle converter handles these specialized conversions automatically, making it valuable for professionals in these fields.
Why Use a Free Online Angle Converter?
Manual angle conversions are time-consuming and prone to calculation errors. A free online tool provides instant, accurate results without registration or software installation. The browser-based converter works on desktop computers, tablets, and smartphones, making it accessible anywhere.
Students benefit by checking homework answers, engineers accelerate project calculations, and professionals working internationally can convert between different regional angle measurement standards instantly. The tool requires no special knowledge—simply enter your value and select your units.
Common Angle Conversions
Memorizing these standard conversions proves helpful: 180 degrees = π radians ≈ 3.14159 rad = 200 gradians. One radian ≈ 57.2958 degrees. A right angle equals 90 degrees, π/2 radians, or 100 gradians. A complete circle is 360 degrees, 2π radians, or 400 gradians.
Using an angle converter eliminates manual calculation of these conversions and ensures precision for complex angles with decimal values.
Tips for Accurate Angle Conversion
Always verify your input unit selection before converting—selecting the wrong unit produces incorrect results. For angles larger than 360 degrees, the converter handles them accurately. When working with very small angles or high-precision measurements, note the decimal places displayed in results.
If converting for academic work, check whether your instructor requires radian answers in terms of π (like π/4) or decimal form (like 0.7854). The angle converter displays both formats for radian conversions.
Conclusion
A free online angle converter streamlines mathematical conversions between degrees, radians, and gradians. Whether for education, engineering, or surveying purposes, this accessible tool eliminates calculation errors and saves valuable time. Start converting your angles today—no registration, no fees, no limitations on the number of conversions.