Math Geometry

Free Online Calculator

Circle Calculator

Find area and circumference instantly.

🧮 ⭕ Circle Calculator

Advanced calculator with modern responsive design.

Calculate area, circumference, diameter, and radius of a circle. Enter any one value to find all others.

From Radius

From Diameter

From Area

From Circumference

📏 Calculate from Radius

Radius (r):

Radius-input

Unit:

Results

📊 Circle Properties

Results

Radius

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units

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Diameter

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units

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Area

Results

square units

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Circumference

Results

units

📐 Calculate from Diameter

Diameter (d):

Diameter-input

Unit:

Results

📊 Circle Properties

Results

Radius

Results

units

Results

Diameter

Results

units

Results

Area

Results

square units

Results

Circumference

Results

units

🔲 Calculate from Area

Area (A):

Area-input

Unit:

Results

📊 Circle Properties

Results

Radius

Results

units

Results

Diameter

Results

units

Results

Area

Results

square units

Results

Circumference

Results

units

🔄 Calculate from Circumference

Circumference (C):

Circumference-input

Unit:

Results

📊 Circle Properties

Results

Radius

Results

units

Results

Diameter

Results

units

Results

Area

Results

square units

Results

Circumference

Results

units

📝 Circle Formulas

Area = π × r²

Circumference = 2 × π × r

Diameter = 2 × r

Radius = d ÷ 2

🔍 Circle Properties & Applications

π (Pi): Approximately 3.14159, the ratio of circumference to diameter

Radius: Distance from center to any point on the circle

Diameter: Distance across the circle through the center (2 × radius)

Area: Amount of space inside the circle

Circumference: Distance around the circle (perimeter)

Applications: Engineering, architecture, manufacturing, astronomy, and everyday measurements

About This Calculator

Our Circle Calculator helps you compute area and circumference with ease.

How We Keep This Calculator Reliable

SaralStudy calculators are built for learning, revision and planning with visible formulas and worked examples.

Formula first Each academic calculator shows the calculation rule before the result so students can verify the method.

Context matters Check units, syllabus context and assumptions before using any answer in homework, lab work or exam preparation.

Educational use Results are study aids, not professional medical, financial, legal or engineering advice.

Study Connections

Continue from this calculator to the matching concepts, formulas and exam practice pages.

NCERT Solutions Use chapter answers before applying formulas or calculators. Important Formulas Revise the formula, units and steps behind each calculation. MCQ Practice Test the same concept with objective questions and quick review. CBSE Sample Papers Apply calculator and formula skills to exam-style questions. Computer Skills Use spreadsheets, documents and presentations with calculations.

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