How this rectangular to polar calculator works
Enter rectangular coordinates x and y. The calculator finds the polar pair (r, θ). r = √(x² + y²) is the distance from the origin, shown to four decimal places. θ = atan2(y, x) converted to degrees is the angle from the positive x-axis, shown to two decimal places with a degree sign. For x=3, y=4 you get r = 5.0000 and theta = 53.13°.
atan2 keeps the correct quadrant. (1, 0) is 0.00°, (0, 1) is 90.00°, (−1, 0) is 180.00°, and (0, −1) is −90.00°. A point such as (−3, 4) stays in the second quadrant with r = 5.0000 and theta = 126.87°. Using plain atan(y/x) would miss those sign cases when x is negative or zero.
Both fields must hold finite numbers. Negatives and decimals are allowed. An empty box leaves r and theta as “--.” At the origin, r is 0.0000 and theta shows 0.00°. Angles typically fall between −180° and 180°.
To reverse the conversion, use x = r cos(θ) and y = r sin(θ) with the same degree measure converted for trigonometry. Check r by squaring x and y, adding, and taking the square root—the same magnitude as a vector length.