🍕 Sector Area & Arc Length Calculator

The “pizza slice” of a circle: its area, arc, chord and segment.

No ratings yet — be the first

Enter details

Log in or create a free account to save your inputs and results, so you don't have to enter them again next time.🔒 No spam, ever. We never sell or share your details, and you can delete your history or account at any time. Privacy policy

Fill in the details and click Calculate to see your results.

Formula at a glance

Sector Area Calculator: Sector area — A = ½r²θ = (θ°/360°)·πr². Example: r = 10 cm, θ = 60° → Sector area: 52.359878 cm²
How the Sector Area Calculator works: Sector area — A = ½r²θ = (θ°/360°)·πr²

Rate this calculator

Was it useful? A quick star rating helps others — and you can leave a comment too.
Rate it: ★ ★ ★ ★ ★

📘 About the Sector Area & Arc Length Calculator

A sector is the part of a circle between two radii — a slice of pizza or a pie-chart wedge. Its area and arc length are the same fraction of the whole circle as its angle is of 360°. The segment is the part between the chord and the arc.

Enter the radius and angle. The calculator gives the sector area, arc length, perimeter, chord length, segment area and the share of the circle, using ½r²θ and rθ with θ in radians (degrees are converted).

🧮 Formula

Sector area
A = ½r²θ = (θ°/360°)·πr²
Arc length
s = rθ = (θ°/360°)·2πr
Chord
c = 2r·sin(θ/2)

✏️ Worked examples

r = 10 cm, θ = 60°

You enter
Radius r10
Central angle θ60
Angle inDegrees
Length unitcm
You get
Sector area52.359878 cm²
Arc length10.471976 cm
Perimeter of the sector30.471976 cm
Chord length10 cm
Segment area (between chord and arc)9.0586074 cm²
Angle60° = 1.0471976 rad
Share of the circle16.6667% (circle area 314.15927 cm²)

Area 52.359878 cm².

r = 5 m, θ = π/2

You enter
Radius r5
Central angle θpi/2
Angle inRadians
Length unitm
You get
Sector area19.634954 m²
Arc length7.8539816 m
Perimeter of the sector17.853982 m
Chord length7.0710678 m
Segment area (between chord and arc)7.1349541 m²
Angle90° = 1.5707963 rad
Share of the circle25% (circle area 78.539816 m²)

Area 19.634954 m².

🧭 How to use this calculator

What you enter

  • Radius r
  • Central angle θ
  • Angle in
  • Length unit

What you get

  • Sector area
  • Arc length
  • Perimeter of the sector
  • Chord length
  • Segment area (between chord and arc)
  • Angle
  • Share of the circle

❓ Frequently asked questions

How do you find the area of a sector?

Multiply the circle’s area by the angle’s share: (θ/360) × πr². For θ = 60° and r = 10, that is 52.36.

What is the difference between a sector and a segment?

A sector is bounded by two radii and an arc; a segment by a chord and an arc.

Why use radians?

In radians the formulas become simple: area ½r²θ and arc rθ.