Semicircle Table: Area by Radius
Reference table of area for Semicircle across a range of radius values — exact, engine-computed figures you can read off at a glance.
Semicircle Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Area
56.5487
- Perimeter
- 30.8496
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Semicircle Calculator
The Semicircle Calculator works out your area, along with 1 related figure in an instant. Enter radius and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the radius.
- Read off your area, together with perimeter — the calculator updates automatically, with no button to press.
Formula
The Semicircle Calculator uses the formula:
Area = 3.141592653589793 × Radius ^ 2 ÷ 2
Worked example
For example, with radius of 6 units, the area is 56.5487.
| Radius | 6 units |
|---|
| Area | 56.5487 |
|---|---|
| Perimeter | 30.8496 |
Results are estimates for educational use, not professional advice.
Key terms explained
- Perimeter
- The total distance around the outside of a two-dimensional shape.
- Radius
- The distance from the centre of a circle or sphere to its edge.
- Area
- The amount of two-dimensional space a shape covers, measured in square units.
Frequently asked questions
Halve the area of the full circle: A = πr² ÷ 2. A semicircle of radius 6 has an area of about 56.55 square units.
It is the half-circle arc plus the straight diameter: πr + 2r. For radius 6 that is about 30.85 units.
No. You must add the diameter, since the flat edge is part of the boundary of a semicircle.
It is twice the radius — the straight edge across the flat side of the half circle.
The Semicircle Calculator uses the formula: Area = 3.141592653589793 × Radius ^ 2 ÷ 2. For example, with radius of 6 units, the area is 56.5487.
Enter the radius. Read off your area, together with perimeter — the calculator updates automatically, with no button to press.
Related guides
How to Calculate Semicircle: Formula, Steps & Examples
Learn how to calculate Semicircle — the formula explained step by step, with worked examples and a free calculator to check your answer.