Circle Sector Calculator
Calculate circle sector area, arc length, and related values from a radius and central angle in degrees or radians.
Formulas:
Area = 1/2 × r² × θ (radians)
Arc length = r × θ (radians)
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Privacy: calculations run locally in your browser. No inputs are stored or transmitted.
How it works
A sector is the slice of a circle bounded by two radii and the connecting arc.
- Sector area: 1/2 × r² × θ (radians)
- Arc length: r × θ (radians)
- Full circle area: πr²
- Circumference: 2πr
Examples
- r = 5, θ = 60° → sector area and arc length
- r = 10, θ = π/2 rad → quarter-circle sector
- r = 3, θ = 180° → semicircle sector
When to use this tool
This tool is designed for quick, practical tasks such as everyday calculations, data formatting, or simple conversions. It is best used when you need fast results without installing software or using complex tools.
When to use
- Quick checks or one-time calculations
- Validating or converting data before using it elsewhere
- Simple tasks that do not require advanced software
When not to use
- Critical financial, legal, or medical decisions
- Large-scale or automated processing
- Situations requiring guaranteed precision beyond basic validation
Always review results before using them in important contexts.
About this tool
This tool helps you perform quick utility operations directly in your browser. It runs entirely in your browser without sending data to a server.
You can use this tool when handling simple tasks without installing additional software. The results should be interpreted as a processed output based on your input data.
FAQ
- What does this circle sector calculator compute?
It computes sector area, arc length, full-circle area, and circumference from a radius and a central angle.
- Can I enter the angle in degrees or radians?
Yes. The calculator supports both degrees and radians.
- What is the formula for sector area?
In radians, sector area = 1/2 × r² × θ. In degrees, sector area = (θ / 360) × πr².
- What is the formula for arc length?
In radians, arc length = r × θ. In degrees, arc length = (θ / 360) × 2πr.
- Are calculations stored?
No. Everything runs locally in your browser.