Geometry calculators

Yes, and consistently. If length is in feet, area comes out in square feet and volume in cubic feet automatically, but only if every input uses the same base unit. Mixing feet and inches in one calculation silently produces a wrong answer with no error shown.

Volume scales with the cube of a linear dimension. So doubling a sphere's radius multiplies its volume by eight, not two. This is why a slightly bigger container often holds far more than intuition suggests.

Surface area measures the total area of a shape's outer boundary: relevant for paint, wrapping or heat loss. Volume measures the space enclosed inside: relevant for capacity or material fill. Both grow with size, but at different rates.

Yes, for any triangle where the three side lengths actually form a valid triangle: meaning any two sides together are longer than the third. If that condition fails, the formula produces a negative number under the square root, which is the calculator's signal that the three lengths cannot form a real triangle.

For the same base radius and height, a cone tapers linearly to a point while a cylinder maintains its full cross-section throughout: integrating that taper over the height works out to exactly one-third the cylinder's volume, a result provable with calculus but true regardless of the specific dimensions.

Split it into rectangles, triangles, trapezoids and circles, work out each one, and add the areas. Subtract any cut-outs. The more pieces you use, the closer the total gets to the true area.

The diameter is the full width through the center and the radius is half of it. Each field label says which one it wants. Entering a diameter where a radius is asked makes an area four times too large and a volume eight times too large.

Area needs the perpendicular distance between the two parallel sides. The slanted side is longer, so using it overstates the area. Measure straight across, at right angles to the bases.

Divide by 9, since a square yard is three feet by three feet. Cubic feet to cubic yards is a division by 27. For any unit, square the linear factor for area and cube it for volume.

Pi is the ratio of a circle's circumference to its diameter, about 3.14159. The calculators use the full precision a computer holds, so rounding only shows in the displayed digits. Using 3.14 by hand is off by about 0.05 percent.

Use the Pythagorean theorem. A rectangle's diagonal is the square root of length squared plus width squared, and a box's space diagonal adds height squared under the same root.

It is about 1.618, the ratio at which the whole is to the longer part as the longer part is to the shorter. It appears in the Fibonacci sequence, in some plants and in design layouts, though many claims about it are exaggerated.

Yes, both measure angle. A full turn is 360 degrees or 2 pi radians. Trigonometric functions in most programs expect radians, while drawings and maps use degrees.

Multiply pi, about 3.14159, by the radius squared, and remember that the radius is half the diameter, so a 10 inch circle has a 5 inch radius.

It relates the sides of a right triangle, where the square of the longest side equals the sum of the squares of the other two.

Area measures a flat surface in square units, and volume measures the space inside a solid in cubic units.