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Circumference Calculator

Just enter only one value to know others.

Radius (r)

cm ▾

Diameter (D)

cm ▾

Circumference (C)

cm ▾

Area (A)

cm ▾

Circumference Calculator

The circumference calculator helps you to calculate circumference, diameter, area, and radius of a circle by entering just one known value. Whether you provide the radius, diameter, area, or circumference, the tool automatically calculates the remaining measurements and presents the full solution with step-by-step explanations for better understanding.

How to Use Circumference of a Circle Calculator?

Just enter any one of the known values
Click ‘Calculate’

How to Calculate Circumference of a Circle?

You can determine the circumference of a circle using the following formula:

C = 2πr

C = πd

Where;

π = Circumference to diameter ratio (3.1416… or 22/7 (Approximately))
r = Radius of circle
D = Diameter of circle

Solved Examples:

Example # 1:

How would you perform circumference calculation if the radius of circle is 3.5 cm?

Solution:

We know that:

C = 2πr

C = 2*3.14*3.5cm

C = 21.98 cm

Also, use the Pythagorean theorem calculator for calculating the length of sides of right-angle triangles.

Example # 2:

If the circle has a diameter of 3 cm, then calculate circumference.

Solution:

Circumference of a circle regarding the diameter is given as:

C = πd

By putting values,

C = 3.14 x 3 cm

C = 9.42 cm

Faqs

Can I use decimals or fractions as input?

Yes, you can enter values in decimals or fractions for more precise calculations.

Does the calculator work for spheres or other shapes?

No, this tool is specifically designed for circles. For spheres, use a surface area or volume calculator.

Why Is Calculating Circumference Important?

The circumference of a circle measures the distance around the whole circle and that is why it is vital.

Does the Circumference Means Length?

Circumference basically deals with arc length. It is similar to the perimeter of other shapes like squares. More precisely, it means that circumference is the length of its boundaries.

What units can I use?

This circumference calculator supports multiple units, including:

Square millimeters (mm²)
Square centimeters (cm²)
Square decimeters (dm²)
Square meters (m²)
Square kilometers (km²)
Square inches (in²)
Square feet (ft²)
Square yards (yd²)
Square miles (mi²)
Ares (a)
Decares (da)
Hectares (ha)
Acres (ac)

Radius to Circumference Table:

Whole Number Values:

Radius (cm)	Diameter (cm)	Circumference (cm)	Area (cm²)
1	2	6.2832	3.1416
2	4	12.5664	12.5664
3	6	18.8496	28.2744
5	10	31.416	78.54
7	14	43.9824	153.9384
10	20	62.832	314.16
20	40	125.664	1256.64

Decimal Values:

Radius (cm)	Diameter (cm)	Circumference (cm)	Area (cm²)
0.5	1	3.1416	0.7854
1.5	3	9.4248	7.0686
2.5	5	15.708	19.635
3.5	7	21.9912	38.4846
0.25	0.5	1.5708	0.19635

Fraction Values:

Radius (cm)	Diameter (cm)	Circumference (cm)	Area (cm²)
½ (0.5)	1	3.1416	0.7854
¾ (0.75)	1.5	4.7124	1.7671
1⅓ (1.333)	2.666	8.3776	5.5851
2½ (2.5)	5	15.708	19.635

References:

SplashLearn (2024) Circumference to Diameter: Conversion, Formula, Meaning, Example. Available at: https://www.splashlearn.com/math-vocabulary/circumference-to-diameter

Study.com (2014) Circumference of a Circle | Formula & Calculation. Available at: https://study.com/academy/lesson/diameter-and-circumference-related-with-pi.html

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Circumference Calculator

Circumference Calculator

How to Use Circumference of a Circle Calculator?

How to Calculate Circumference of a Circle?

Solved Examples:

Example # 1:

Solution:

Example # 2:

Solution:

Faqs

Can I use decimals or fractions as input?

Does the calculator work for spheres or other shapes?

Why Is Calculating Circumference Important?

Does the Circumference Means Length?

What units can I use?

Radius to Circumference Table:

Whole Number Values:

Decimal Values:

Fraction Values:

References:

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