As you probably already know, a sphere is a 3D geometric shape that’s perfectly round. A real-life example would be a baseball or soccer ball. The formula for working out a sphere’s volume is:
*Volume = (4/3) x π x r³*
In most circumstances, you won’t know what the radius is, but if you use a piece of string, you can often work out the circumference instead. The circumference of a sphere is the 1D distance around the widest point of the round item.
*Circumference = 2 x π x r*
**Which means:**
*r = circumference / (2 x π)*

Let’s say you want to find out the volume of a junior player’s size five basketball.
1. Identify the radius data of the sphere. A junior size five basketball has a 4.4-inch radius.
2. Once you enter the radius data, the remaining data appears. A junior basketball has a circumference of 27.5 inches and a volume of 351 cubic inches.
What about something bigger, like Planet Earth? The radius for Earth is 6.37 x 10 6m. Therefore, you would measure the volume like this:
*Volume = (4/3) x π x (6370000 m) ³ = 1,082,696,932,430,002,306,149 m³*

A spherical cap or spherical dome is where a plane cuts off a portion of a sphere. There is a special volume to perform the calculation:
*Volume = ((π * h²) / 3) x (3r - h)*
**or**
*Volume = (1/6) x π x h x (3a² + h²)*
R = radius
H = height of the cap
A = radius of the cap’s base
Let’s say your spherical cap is a fishbowl, and you want to work out how full to fill your bucket for the fish tank. You would follow these instructions below.
1. Identify the cap’s height. For this example, it’s 10 inches.
2. Identify the radius on the cap’s base. For the fishbowl in this example, it’s 4.5.
3. Enter the data into the calculator to find out the answer. The sphere radius is six inches, and the volume is 842 cubic inches.

If you need to know how to calculate the volume for the hemisphere, then use the same spherical cap volume as above. Make sure the parameters are the same.
The Sphere Radius = Height of the **Cap = Cap Base Radius**. You can then divide the sphere into two parts.

Measuring the volume of a sphere is the tip of the iceberg. You can also use a measure the volume of a cone, or convert volume units from one measurement type to another.