Arc Length & Sector Area Calculator

This calculator finds the arc length, sector area and chord length of a circle from its radius and a central angle, the three quantities you most often need when working with a slice of a circle. A sector is the pie-shaped region between two radii, like a slice of cake or a segment of a pie chart, and its dimensions come up constantly in geometry, design, engineering and construction, from setting out curved paths and roads to designing gears, fan blades and architectural curves. The arc length is the curved distance along the circle's edge that bounds the sector, the sector area is the area of the slice itself, and the chord is the straight line joining the two ends of the arc. Each follows directly from the radius and the central angle. This tool computes all three together. You enter the radius and the central angle in degrees, and the calculator returns the arc length, the sector area, the chord length, and the angle converted to radians for reference. The results update as you type, so you can see how a wider angle lengthens the arc and grows the slice. Use it for geometry homework, for laying out curves in construction or landscaping, for design work, or any time you need the dimensions of a circular sector. A full angle of 360 degrees gives the whole circumference and the whole circle's area, while 180 degrees gives a semicircle, which are useful checks. The calculations use the standard circle formulas, with the angle handled in radians internally, and the results are rounded for display.

Arc = r x angle (radians). Sector area = half x r squared x angle (radians). Chord = 2r x sine of half the angle. Rounded for display.