Circle Radius from Area Table: Radius by Circle area
Reference table of radius for Circle Radius from Area across a range of circle area values — exact, engine-computed figures you can read off at a glance.
Circle Radius from Area Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Radius
5.000006
- Diameter
- 10.0000
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Circle Radius from Area Calculator
The Circle Radius from Area Calculator works out your radius, along with 1 related figure in an instant. Enter circle area 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 circle area.
- Read off your radius, together with diameter — the calculator updates automatically, with no button to press.
Formula
The Circle Radius from Area Calculator uses the formula:
Radius = √(Circle area ÷ 3.141592653589793)
Worked example
For example, with circle area of 78.54, the radius is 5.000006.
| Circle area | 78.54 |
|---|
| Radius | 5.000006 |
|---|---|
| Diameter | 10.0000 |
Results are estimates for educational use, not professional advice.
Key terms explained
- Diameter
- The distance across a circle through its centre — twice the radius.
- 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
Divide the area by π and take the square root. An area of 78.54 gives a radius of 5.
Radius = √(area ÷ π), the inverse of the area formula πr².
Double the radius. The calculator shows the diameter alongside the radius.
It is useful when you know the area, such as a footprint or coverage, and need the radius or diameter.
Enter the circle area. Read off your radius, together with diameter — the calculator updates automatically, with no button to press.
Related guides
How to Calculate Circle Radius from Area: Formula, Steps & Examples
Learn how to calculate Circle Radius from Area — the formula explained step by step, with worked examples and a free calculator to check your answer.