Geometry calculators
Geometry calculators for areas, volumes, angles, and shapes. Whether you need the area of a circle or the volume of a cone, the formula and a worked example are included.
17 calculators
- Acute Triangle Calculator
Type three side lengths and the calculator checks whether they form an acute triangle (every angle strictly less than 90°), reports all three angles via the law of cosines, and gives the area from Heron's formula.
- Annulus (Ring) Area Calculator
Enter the outer and inner radii of a flat circular ring and the calculator returns the annulus area A = π(R² − r²), along with the ring width and the two bounding circumferences.
- Area of an Oblique Triangle Calculator
An oblique triangle is any triangle without a right angle. Enter two sides and the angle between them; the calculator returns the area via ½·a·b·sin(C), plus the missing side and angles from the laws of cosines and sines.
- Centroid of a Triangle Calculator
Enter the (x, y) coordinates of the three vertices. The calculator returns the centroid — the intersection point of the three medians — along with each side midpoint, the three median lengths, and the triangle area.
- Circle Calculator
Pick which property of the circle you know — radius, diameter, circumference or area — type the value, and the calculator returns the other three using exact π.
- Cone Volume Calculator
Type the base radius and height of a right circular cone — the calculator returns volume, slant height, lateral and total surface area, all using exact π.
- Cylinder Volume Calculator
Type the radius and height of a right circular cylinder — the calculator returns volume, base area, lateral (curved) surface and total surface, all using exact π.
- Ellipse Area Calculator
Type the two semi-axes of your ellipse and the calculator returns the area, an accurate perimeter approximation, the eccentricity and the focal distance.
- Hexagon Calculator
Type the side length of a regular hexagon. The calculator returns the area, perimeter, apothem, long diagonal, width across the flats and circumradius — all from one input.
- Lateral Area of a Trapezoidal Prism Calculator
Type the four sides of the trapezoid base (two parallel sides a, b and two legs c, d) and the prism length L — the calculator returns the lateral surface area and each of the four rectangular face areas.
- Pythagorean Theorem Calculator
Solve a² + b² = c² for any side of a right triangle, with area, perimeter and angles shown alongside.
- Slope Calculator
Type the (x, y) coordinates of two points. The calculator returns the slope of the line through them plus the full line equation, midpoint, straight-line distance and the angle the line makes with the x-axis.
- Sphere Volume Calculator
Type the radius of a sphere — the calculator returns volume, surface area, diameter, circumference and great-circle area, all using exact π.
- Surface Area Calculator
Pick a solid — cube, sphere, cylinder, cone or square pyramid — enter its dimensions and get the total surface area, plus the lateral and base components, in any unit.
- Tank Volume Calculator
Pick a tank shape — vertical cylinder, horizontal cylinder, or rectangular box — enter the dimensions and (optionally) a liquid depth. Get total volume, filled volume, head space and fill percent.
- Tetrahedron Volume Calculator
Type the edge length of a regular tetrahedron — the calculator returns volume, face area, total surface area, height, insphere and circumsphere radii using exact square roots.
- Triangle Calculator
Solve any triangle from three known measurements — sides, angles, area and perimeter, with the laws of sines and cosines doing the work behind the scenes.