Calculadora de Geometría
Calcula área, perímetro y más para cualquier figura 2D
Geometry Calculator
Calculate properties of circles, triangles, and rectangles
Enter radius to compute area, circumference, and diameter
Area = pi x r2, Circumference = 2 x pi x rWhat is a Geometry Calculator?
A Geometry Calculator is a math tool that helps you calculate common geometric measurements such as area, perimeter, circumference, surface area, volume, and missing side lengths. Geometry focuses on shapes and space—like circles, triangles, rectangles, and 3D objects such as cylinders and spheres.
Instead of memorizing multiple formulas and doing the arithmetic by hand, a geometry calculator lets you enter the measurements you already know (like radius, length, width, base, height, or side lengths) and instantly computes the result. This is useful for students learning geometry, as well as real-world tasks like home projects, construction planning, packaging, landscaping, and design.
Many geometry problems are simple in concept but easy to mess up with unit conversions or formula mistakes. A calculator reduces errors and saves time, especially when working with decimals, large measurements, or multiple shapes.
How to Use This Geometry Calculator
- Choose the shape or calculation type -- example: circle area, rectangle perimeter, triangle area, cylinder volume
- Enter the required measurements -- such as radius, side lengths, base, height, length, width
- Select units if supported -- cm, inches, feet, meters, etc.
- Click "Calculate" -- to compute the result
- Review the output -- check that the unit makes sense (square units for area, cubic units for volume)
Tips:
- Use consistent units for all inputs (don't mix inches and feet unless you convert first)
- Area results are in square units (e.g., ft²), and volume results are in cubic units (e.g., ft³)
- If your result seems too large or too small, double-check the inputs—most errors come from entering the wrong unit or swapping height/width
Geometry Formulas
2D Shapes (Area and Perimeter)
Rectangle
- Area = length x width
- Perimeter = 2(length + width)
Square
- Area = side²
- Perimeter = 4 × side
Triangle
- Area = (base × height) ÷ 2
- Perimeter = side1 + side2 + side3
Circle
- Area = πr²
- Circumference = 2πr
Where r = radius and π ≈ 3.14159
Right Triangle (Pythagorean Theorem)
a² + b² = c²
Where c is the hypotenuse (the longest side)
3D Shapes (Surface Area and Volume)
Rectangular Prism (Box)
- Volume = length × width × height
- Surface Area = 2(lw + lh + wh)
Cylinder
- Volume = πr²h
- Surface Area = 2πr² + 2πrh
Sphere
- Volume = (4/3)πr³
- Surface Area = 4πr²
Example Calculations
Example 1: Area of a Circle
Radius (r): 7
Formula: Area = πr²
Calculation: π × 7² = π × 49 ≈ 153.94
Result: Area ≈ 153.94 square units
Example 2: Perimeter of a Rectangle
Length: 12, Width: 8
Formula: Perimeter = 2(length + width)
Calculation: 2(12 + 8) = 2 × 20 = 40
Result: Perimeter = 40 units
Example 3: Area of a Triangle
Base: 10, Height: 6
Formula: Area = (base × height) ÷ 2
Calculation: (10 × 6) ÷ 2 = 60 ÷ 2 = 30
Result: Area = 30 square units
Example 4: Volume of a Cylinder
Radius (r): 3, Height (h): 10
Formula: Volume = πr²h
Calculation: π × 3² × 10 = π × 9 × 10 = 90π ≈ 282.74
Result: Volume ≈ 282.74 cubic units
Frequently Asked Questions
What's the difference between perimeter and area?
Perimeter is the distance around a 2D shape (measured in units like cm or inches). Area is the space inside a 2D shape (measured in square units like cm² or in²).
Why do circle formulas use π (pi)?
π is the constant ratio of a circle's circumference to its diameter. It appears in circle formulas because circles are defined by that constant relationship. A common approximation is π ≈ 3.14159.
What units should I use for geometry calculations?
Use consistent units for all inputs. If you measure length in inches, keep all values in inches. The output will follow the same unit system (square inches for area, cubic inches for volume).
How do I calculate a missing side in a right triangle?
Use the Pythagorean theorem: a² + b² = c². If you know two sides, you can solve for the third by rearranging the equation.
Why is my area or volume result "too big"?
The most common causes are entering values in the wrong unit (feet vs inches), mixing units without converting, or confusing radius with diameter (diameter is twice the radius).
Want to add this geometry calculator to your website? Get a custom embed code that matches your site's design and keeps visitors engaged.
¿Qué es la geometría y por qué importa?
La geometría es la rama de las matemáticas que estudia el tamaño, la forma y las propiedades de las figuras y los espacios. Desde las dimensiones de una cerca hasta los planos de un edificio, la geometría está en todas partes. Los constructores la usan para hacer cimientos, los artistas para diseñar composiciones, los ingenieros para mediciones precisas y los topógrafos para delimitar propiedades. Entender los cálculos básicos de geometría es útil de verdad en la vida cotidiana.
Esta calculadora de geometría elimina el trabajo manual al calcular propiedades de figuras 2D. Ya seas estudiante resolviendo una tarea, un contratista estimando cuánto piso necesitas o un aficionado planeando el diseño de un jardín, obtendrás resultados precisos de área, perímetro y circunferencia en segundos. Cada resultado incluye la fórmula correspondiente para que veas exactamente cómo se obtuvo la respuesta.
Cómo usar la calculadora de geometría
- Selecciona la figura que quieres calcular: círculo, triángulo, rectángulo, cuadrado o trapecio.
- Ingresa las dimensiones conocidas para esa figura (radio, base, altura, longitudes de lados, etc.).
- Haz clic en el botón Calcular para ejecutar el cálculo.
- Lee los resultados: área, perímetro (o circunferencia para círculos) y otras medidas relevantes se muestran al instante.
Fórmulas de geometría de un vistazo
Círculo: A = πr², C = 2πr
Triángulo: A = ½ × base × altura
Rectángulo: A = l × w, P = 2(l + w)
Cuadrado: A = s², P = 4s
Trapecio: A = ½(a + b) × hEn todas las fórmulas de círculos, π ≈ 3.14159. Asegúrate de que todas las dimensiones estén expresadas en la misma unidad antes de calcular: mezclar centímetros y metros, por ejemplo, dará un resultado incorrecto.
Ejemplos resueltos
Círculo con radio 5 cm
Usando A = πr²: A = π × 5² = π × 25 ≈ 78.54 cm². Usando C = 2πr: C = 2 × π × 5 ≈ 31.42 cm. Un círculo con radio de 5 cm tiene un área de aproximadamente 78.54 cm² y una circunferencia de aproximadamente 31.42 cm.
Rectángulo de 8 m × 3 m
Área: A = l × w = 8 × 3 = 24 m². Perímetro: P = 2(l + w) = 2(8 + 3) = 2 × 11 = 22 m. Útil para calcular cuántos azulejos necesitas (área) y cuánto zócalo comprar (perímetro).
Triángulo con base 10 pies y altura 6 pies
Área: A = ½ × base × altura = ½ × 10 × 6 = 30 ft². Esta fórmula funciona para cualquier triángulo — rectángulo, isósceles o escaleno — siempre que tengas la altura perpendicular desde la base.