Circles & Ellipses
Calculators and formulas for circles, ellipses and related round shapes
10+
Circle calculators
Area
Computations
Angles
Functions
Curves
Calculations
Basic shapes: Circle & Ellipse
Circle arcs & sectors
Annular & hollow shapes
Special curves & constructions
What makes our circle calculators special?
High-precision calculations
Exact computations using π and trigonometric functions for highest accuracy.
Visual representation
Graphical display of circle shapes with labeled parameters.
Comprehensive theory
Detailed mathematical derivations and historical context.
Related calculator categories
2D Geometry
Related areas
Quick access for common calculations
Mathematical foundations of circle geometry
Circles and π (Pi)
The circle is a fundamental geometric form with the constant π ≈ 3.14159. All circle calculations are based on relations between radius, diameter, circumference and area. π links circumference and diameter universally.
Practical applications
Circle calculations are essential in mechanical engineering, architecture, physics and engineering. From bearings to planetary orbits, from pipes to satellite dishes — circular structures appear everywhere.
Historical significance of circle geometry
Ancient mathematics
Babylonians and Egyptians knew approximations for π. Archimedes computed bounds for π with inscribed and circumscribed polygons and laid foundations of circle geometry.
Classical problems
"Squaring the circle" occupied mathematicians for over 2000 years. In 1882 Lindemann proved the impossibility of this construction with straightedge and compass.
Modern developments
Today computers compute π to trillions of digits. Circle geometry is fundamental for GPS, satellite technology and modern physics.