Geometry
Geometry tools solve the shape questions that show up in homework, DIY and site work: triangles, circles, area, volume and surface area.
Pick one length unit and the page keeps area (unit²) and volume (unit³) distinct so sides and volumes are never mixed.
Featured in this category
Triangle Calculator
Find a triangle’s area, perimeter and angles from three sides, or the area from base and height or SAS.
Area Calculator
Find the area of a square, rectangle, triangle, circle, trapezoid, parallelogram or ellipse.
Pythagorean Theorem
Find the hypotenuse from two legs, or a missing leg from the hypotenuse and the other leg.
2D Geometry
Area Calculator
Find the area of a square, rectangle, triangle, circle, trapezoid, parallelogram or ellipse.
Circle Calculator
From radius, diameter or circumference, get the other two plus the area of a circle.
Slope Calculator
Find the slope of a line from two points or from rise and run, plus the angle from the positive x-axis.
3D Geometry
Triangles & Distance
Triangle Calculator
Find a triangle’s area, perimeter and angles from three sides, or the area from base and height or SAS.
Right Triangle
From two legs, or a leg and the hypotenuse, get the third side, both acute angles, area and perimeter.
Pythagorean Theorem
Find the hypotenuse from two legs, or a missing leg from the hypotenuse and the other leg.
Distance Calculator
Find the straight-line distance between two points in a plane or in 3-D space.
All geometry tools
Search or scan the full list for this category.
9 tools
Triangle Calculator
Find a triangle’s area, perimeter and angles from three sides, or the area from base and height or SAS.
Volume Calculator
Find the volume of a cube, box, sphere, cylinder, cone or rectangular pyramid in unit³.
Slope Calculator
Find the slope of a line from two points or from rise and run, plus the angle from the positive x-axis.
Area Calculator
Find the area of a square, rectangle, triangle, circle, trapezoid, parallelogram or ellipse.
Distance Calculator
Find the straight-line distance between two points in a plane or in 3-D space.
Circle Calculator
From radius, diameter or circumference, get the other two plus the area of a circle.
Surface Area
Find the total surface area of a cube, box, sphere, cylinder or cone, including slant height for a cone.
Pythagorean Theorem
Find the hypotenuse from two legs, or a missing leg from the hypotenuse and the other leg.
Right Triangle
From two legs, or a leg and the hypotenuse, get the third side, both acute angles, area and perimeter.