Geometry
Areas, volumes, triangles, solids · 18 calculators
18 calculators
Triangle (full)
All sides + angles
OpenRight Triangle
Two legs → hyp + area
OpenEquilateral Triangle
Area + height
OpenPythagorean Theorem
c² = a² + b²
OpenCircle
Area, circ, diameter
OpenEllipse
Area + perimeter
OpenSquare
Side → area, diagonal
OpenRectangle
L×W → area, perimeter, diag
OpenParallelogram
Base × height
OpenTrapezoid
(a+b)·h / 2
OpenRegular Polygon
n sides + side length
OpenCube
Volume + surface
OpenCuboid
L × W × H
OpenSphere
4/3·π·r³
OpenCylinder
π·r²·h
OpenCone
π·r²·h/3
OpenPyramid
Base² × h / 3
OpenTorus
Donut volume + surface
Open
Frequently asked about the Geometry
What geometry calculators do you have?
18 shapes: triangle (right, equilateral, general / Heron's), Pythagorean theorem, circle, ellipse, square, rectangle, parallelogram, trapezoid, regular polygon (n sides), cube, cuboid, sphere, cylinder, cone, pyramid, torus. Each computes area, volume, surface, perimeter, slant height as applicable.
Is everything in SI units?
Inputs are dimensionless — type 5 meters or 5 feet, the math holds. Outputs use the same unit, so a 5×5×5 cube has volume 125 (in your chosen unit cubed). For unit conversion of the result, use the Length / Area / Volume converters.
Does it support coordinate geometry?
Slope, distance (2D), and Pythagorean theorem cover the common cases. Full coordinate-geometry (line equations, conic sections, transformations) is on the roadmap.
Triangle solver — what do I need to input?
All three sides for area (Heron's formula). For the right-triangle calculator: any two sides → hypotenuse, area, perimeter, both angles. The general-triangle calculator from sides gives perimeter + area + all three interior angles.
Why isn't my obtuse triangle valid?
Triangle inequality: each side must be less than the sum of the other two. If you enter 1, 2, 5 — there's no real triangle. The calculator returns 0 area in that case.
Do you have torus / dodecahedron / icosahedron?
Torus is included. Platonic-solid calculators (dodecahedron, icosahedron, tetrahedron) are coming in the next geometry expansion. For most engineering / DIY use cases, cube / cylinder / cone / sphere cover 95% of needs.