1. What does this tool do
This free online radian degree converter converts between radians and degrees instantly. Use it for degrees to radians or radians to degrees in trigonometry, physics, or programming when you need angles in the right representation. Enter an angle in either unit and see the equivalent; set 0–10 decimal places. No sign-up, no upload; everything runs in your browser. Ideal for trigonometry, physics, education, or APIs that use radians.
2. How to use it
Quick start: Choose "Degrees → Radians" or "Radians → Degrees", enter a numeric angle, set decimal places if needed, then view and copy the result. Use Load sample for 180° or π rad.
- Select mode — Choose "Degrees → Radians" to convert from degrees to radians, or "Radians → Degrees" for the reverse.
- Set decimal places — Select how many decimal places you want in the result (0–10). Default is 6.
- Enter input — Type a numeric angle. Examples: for degrees use 180 or 90; for radians use 3.14159 or 1.5708.
- View output — The converted value appears instantly. Copy with one click.
- Sample or clear — Use Load sample to try an example (180° or π rad), or Clear to reset.
3. How it works
Degrees to radians: radians = degrees × (π / 180). One full rotation (360°) equals 2π radians. Radians to degrees: degrees = radians × (180 / π). The tool uses JavaScript's Math.PI for the conversion. Input is validated: empty, non-numeric, and infinite values are rejected. All computation runs entirely in your browser. No data is sent to any server.
4. Use cases & examples
- Trigonometry — Convert angles between degrees (e.g. 30°, 45°, 90°) and radians for use with
Math.sin,Math.cos, etc., which expect radians. - Physics — Angular velocity, phase angles, and wave equations often mix degrees and radians.
- Education — Teach or learn the relationship between degrees and radians; understand that π rad = 180°.
- Programming — Many APIs use radians; convert user input in degrees to radians before calling trig functions.
Examples
180(degrees) → 3.141592653589793 (π)90(degrees) → 1.5707963267948966 (π/2)3.14159(radians) → ~180 (degrees)
5. Limitations & known constraints
- Number precision — JavaScript's Number type has about 15–17 significant digits. Very long decimal strings may lose precision.
- Input length — Maximum 100 characters to avoid performance issues.
- Infinity & NaN — Not supported; the tool rejects non-finite values.
- Symbol π — The placeholder shows "π" as an example; actual input must be numeric (e.g. 3.14159). The tool does not parse the Greek letter π.