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Reference & Coterminal Angle Calculator

Enter any angle in degrees or radians to get its reference angle, its quadrant, and positive and negative coterminal angles — with a diagram and steps.

Reference angle: the acute angle to the x-axis · Coterminal: θ + 360°·n
angle θ °

Enter any angle (positive or negative). You'll get its reference angle, quadrant, and coterminal angles.

Results

Reference angle
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Normalized angle (0–360°)
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Quadrant
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Least positive coterminal
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A negative coterminal
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General coterminal angles
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Diagram

Terminal sideReference angle

Step-by-step