Plane Geometry Calculators

Plane Geometry & Trigonometry Calculators

Free, responsive calculators for geometry, triangles, coordinates and trigonometry.

Calculators

Annulus Calculator

Calculate the area and circumference of an annulus (ring).

Outer Radius R

Inner Radius r

Result

—

Area = π(R² − r²)
Outer Circumference = 2πR
Inner Circumference = 2πr

Circle Calculator

Enter radius to calculate diameter, circumference and area.

Radius

Result

—

Diameter = 2r
Circumference = 2πr
Area = πr²

Two-Dimensional Distance Calculator

x₁

y₁

x₂

y₂

Result

—

d = √[(x₂ − x₁)² + (y₂ − y₁)²]

Parallelogram Calculator

Base

Side

Height

Result

—

Area = base × height
Perimeter = 2(base + side)

Rectangle Calculator

Length

Width

Result

—

Area = length × width
Perimeter = 2(length + width)
Diagonal = √(length² + width²)

Regular Polygon Calculator

Number of Sides 3 4 5 6 7 8 9 10 11 12 13 14

Side Length

Result

—

Perimeter = n × s
Area = n × s² / (4 tan(π/n))

Rhombus Calculator

Diagonal d₁

Diagonal d₂

Result

—

Area = d₁d₂ / 2
Side = √[(d₁/2)² + (d₂/2)²]
Perimeter = 4 × side

Square Calculator

Side Length

Result

—

Area = s²
Perimeter = 4s
Diagonal = s√2

Stadium Calculator

A stadium consists of a rectangle with semicircles on both ends.

Straight Length L

Radius r

Result

—

Area = 2rL + πr²
Perimeter = 2L + 2πr

Trapezoid Calculator

Base a

Base b

Base c

Base d

Height

Result

—

Area = (a + b)h / 2
Perimeter = a + b + c + d

Slope Calculator

x₁

y₁

x₂

y₂

Result

—

m = (y₂ − y₁) / (x₂ − x₁)

Midpoint Calculator

x₁

y₁

x₂

y₂

Result

—

M = ((x₁ + x₂)/2, (y₁ + y₂)/2)

Law of Cosines Calculator

Side a

Side b

Included Angle C (degrees)

Result

—

c² = a² + b² − 2ab cos(C)

Law of Sines Calculator

Side a

Angle A (degrees)

Angle B (degrees)

Result

—

a/sin(A) = b/sin(B)

Pythagorean Theorem Calculator

Leg a

Leg b

Result

—

c = √(a² + b²)

Equilateral Triangle Calculator

Side

Result

—

Area = √3s² / 4
Height = √3s / 2
Perimeter = 3s

Isosceles Triangle Calculator

Equal Side a

Base b

Result

—

Height = √(a² − (b/2)²)
Area = bh/2
Perimeter = 2a + b

Right Triangle Calculator

Leg a

Leg b

Result

—

c = √(a² + b²)
Area = ab/2

Trigonometry Calculator

Calculate sine, cosine, tangent, inverse trigonometric functions and angle conversions.

Value / Angle

Function sin cos tan sin⁻¹ cos⁻¹ tan⁻¹ Degrees → Radians Radians → Degrees

Result

—

For sin, cos and tan the input is interpreted as degrees.

Plane Geometry & Trigonometry Calculator Tool