Sphere Calculator: Simple and Fast Calculations

Calculate all sphere properties by entering any known measurement. The tool automatically computes radius, diameter, volume, surface area, and circumference.

Worked example: radius = 6 cm

Select "Radius" as the input type, enter 6, and choose cm as the unit. The calculator derives every other property from that single radius value:

Diameter:      d = 2r = 2 × 6 = 12 cm
Volume:        V = (4/3)πr³ = (4/3)π(6³) = (4/3)π(216) = 288π ≈ 904.7789 cm³
Surface Area:  A = 4πr² = 4π(6²) = 4π(36) = 144π ≈ 452.3893 cm²
Circumference: C = 2πr = 2π(6) = 12π ≈ 37.6991 cm

Note the exponents: volume scales with r³ (cubic), while surface area and circumference scale with r² and r¹ respectively. That's why doubling a sphere's radius multiplies its volume by 8 but only multiplies its surface area by 4 — a detail that matters in physics and engineering contexts like heat dissipation or material cost estimates.

Working backward from volume or surface area

If you select "Volume" as the input type instead and enter 904.7789, the tool solves the volume formula for r: r = ((3V)/(4π))^(1/3), recovering radius ≈ 6. Selecting "Surface Area" and entering 452.3893 solves r = √(A/(4π)) the same way — both input modes converge on the identical radius, diameter, volume, surface area, and circumference table.

Unit handling

The unit selector (mm, cm, m, in, ft) is applied uniformly — the calculator does not perform unit conversion between them, it simply labels the output with whatever unit you selected for the input. Entering "6" with unit "in" computes the same numeric result as "6" with unit "cm," just labeled differently.