Reference Angle Calculator
Enter any angle \u2014 huge, tiny, or negative. Get the normalized angle, the quadrant, and the reference angle, with steps.
For radians you can type a decimal or a \u03C0-form like 7pi/6.
③ WHY IT WORKS
Why reference angles work
Trig values repeat every 360\u00B0 and mirror across the axes, so every angle behaves like one acute angle plus a sign rule. The reference angle is that acute angle \u2014 the smallest angle between the terminal side and the x-axis \u2014 and the quadrant decides whether sine, cosine, and tangent come out positive or negative.