Geometry Calculator
Calculate and convert area, perimeter, surface area, and volume for common shapes.
Workspace
Preparing geometry reports…
Shape calculator
Choose a shape and measurements
The unit used by your input measurements.
Convert area and volume automatically.
Live result
Circle
Formula usedPreparing formula…
All measurements must use the same input unit. Converted square and cubic units apply the conversion factor twice or three times.
GuideHow to use
- Choose a 2D or 3D shape, then enter every requested measurement using one input unit.
- Optionally choose a different result unit and decimal precision; square and cubic conversions update automatically.
- Review the live formula and measurements, then copy the summary or download it as CSV.
HelpFrequently asked questions
How do I calculate the area of a triangle from three sides?
Enter all three side lengths. The system uses Heron's formula to calculate area directly from the side lengths, without needing a separate height measurement.
What is the difference between surface area and volume?
Surface area is the total area covering the outside of a 3D shape. Volume is the amount of space it encloses.
Why did my triangle show an error?
Three side lengths can only form a triangle when each side is shorter than the sum of the other two. If that is not true, no such triangle exists.
How are area and volume units converted?
A length conversion is applied twice for square units and three times for cubic units. For example, converting metres to centimetres multiplies area by 10,000 and volume by 1,000,000.
How accurate is the ellipse circumference?
Ellipse circumference has no simple elementary formula. This calculator uses Ramanujan's highly accurate approximation.
Keep working
Related tools
Calculators & MathUnit Converter
Convert length, mass, temperature, speed, pressure, energy, volume, time, area, and data units.
Calculators & MathPercentage Calculator
Calculate percentage amounts, change, difference, increases, decreases, discounts, and original values.
Calculators & MathAverage & Statistics Calculator
Calculate averages, quartiles, percentiles, spread, deviation, frequency, distribution, and possible outliers.