Unit Circle Reference
Interactive unit circle with all key angles and values. Free online unit circle reference tool.
The Unit Circle Reference is an interactive tool displaying all key angles and their trigonometric values on the unit circle. Find sine, cosine, and tangent values for standard angles in both degrees and radians. This visual reference is invaluable for trigonometry students, engineers, and anyone working with circular functions and rotations.
Common use cases
- Learning trigonometry
- Quick reference for standard values
- Verifying trig calculations
- Teaching and tutoring
- Engineering angle calculations
How to use
- View the unit circle diagram
- Select any standard angle
- See coordinates (cos θ, sin θ)
- View exact values as fractions
- Use the interactive angle selector
FAQ
What is the unit circle?
A circle with radius 1 centered at the origin. Any point (x, y) on it satisfies x² + y² = 1.
Why are coordinates (cos θ, sin θ)?
On the unit circle, the x-coordinate equals cos(θ) and y-coordinate equals sin(θ) for angle θ from positive x-axis.
What angles should I memorize?
Key angles: 0°, 30°, 45°, 60°, 90° and their multiples around the circle.
What about tangent?
tan(θ) = sin(θ)/cos(θ) = y/x, representing the slope of the line from origin to the point.