Examples
- r = 5 → Area ≈ 78.54, Circumference ≈ 31.42
Frequently asked questions
What is π?
≈ 3.14159, the ratio of circumference to diameter.
Circle Calculator
Compute area, circumference and diameter from a radius.
Related calculators
Percentage Calculator
Calculate percentages, find what percent one number is of another, and track percentage c…
Scientific Calculator
Solve complex math problems instantly with our free online scientific calculator, featuri…
Fraction Calculator
Easily add, subtract, multiply, and divide fractions. Get the simplified fractional resul…
Ratio Calculator
Simplify any ratio A:B to its lowest terms.
Proportion Calculator
Solve for the missing value in a proportion A:B = C:D.