Geometry Calculators

Free online geometry calculators for 2D shapes, 3D shapes, and trigonometry. Fast, Free, Accurate.

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2D Shape Calculators
Free area and perimeter calculators for circles, rectangles, squares, and triangles. Multiple input methods, all formulas shown.
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3D Shape Calculators
Free volume and surface area calculators for spheres, cylinders, cubes, and cones. All formulas shown with worked examples.
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Trigonometry Calculators
Free sin, cos, tan, Pythagorean theorem, and triangle solver calculators. All six trig ratios, degree and radian modes, law of sines and cosines.

Geometry Calculators - Area, Volume, and Trigonometry Solved Instantly

Geometry is the foundation of architecture, design, construction, manufacturing, and academic mathematics. Whether you need the area of a circle for a landscaping project, the volume of a cylinder for an engineering spec, or the angles of a triangle for a surveying problem, NeutronDB’s geometry calculators deliver precise results with full formula breakdowns.

Three Subcategories for Every Geometric Problem

🔷 2D Shapes Area and perimeter for circles, rectangles, squares, triangles 🎲 3D Shapes Volume and surface area for spheres, cylinders, cones, cubes 📐 Trigonometry Sin/cos/tan, Pythagorean theorem, triangle solver

Most-Used Geometry Calculators

For everyday construction and design, the Rectangle Calculator handles rooms and plots, while the Circle Calculator handles anything round - gardens, pipes, wheels. The Triangle Calculator supports three input methods including Heron’s formula for when you only know the three side lengths.

For 3D work, the Cylinder Calculator is used constantly for concrete columns, storage tanks, and pipes. The Cone Calculator adds slant height and lateral surface area for hopper and roof calculations.

For angle work, the Pythagorean Theorem Calculator verifies right angles on construction sites, and the Triangle Solver handles any triangle configuration using the law of sines and cosines.

Real-World Applications

Flooring and tiling - Calculate room area with the Rectangle Calculator, divide by tile size, add 10% wastage. Concrete volumes - Use the Cylinder Calculator for columns and the Cube Calculator for rectangular footings. Physics vectors - Decompose forces using sin and cos.

Frequently Asked Questions

Which triangle formula does the triangle calculator use?

The Triangle Calculator supports three methods: base × height ÷ 2, Heron's formula (all three sides), and ½ab·sin(C) for two sides and an included angle. Select the mode that matches your known values.

How do I calculate the volume of a hollow cylinder?

Use the Cylinder Calculator twice - once for the outer radius and once for the inner radius - then subtract. The formula is π × h × (R² − r²).

Does the Pythagorean theorem calculator work for all right triangles?

Yes. The Pythagorean Theorem Calculator accepts any two sides and solves for the third, also displaying all three vertex angles.

Are angles in degrees or radians?

The Sin Cos Tan Calculator and Triangle Solver default to degrees with a radian toggle available.