Why do I need that, some will ask. If flower pots aren't labeled with their capacity, purchasing potting soil can only be guesswork. So that no earth is left over, an exact calculation is advantageous.
The formula for calculating the volume of a flower pot depends on the shape
Calculate the volume of flower pots
Mathematical formulas help here, but few people know them by heart. So here is some help.
There are different flower pot shapes:
- dice
- cuboid
- hemisphere
- truncated cone
The cube shape
Mathematical formula: length x width x height. Since all sides of the cube are the same length, measure only one side, for example 20 cm. Then calculate 20 cm x 20 cm x 20 cm = 8000 cm³
1000 cm³ equals 1 liter, so the cube has a volume of 8 liters.
The square
Here, too, length x width x height is calculated, for example 50 cm long, 20 cm wide and 15 cm high. The calculation is 50 cm x 20 cm x 15 cm = 15000 cm³, i.e. 15 liters.
The hemisphere
Here it gets a little more difficult. Use the formula: V = 1/12 x pi x d³
V stands for volume
pi stands for the corresponding number 3.1415926535… , short 3.14
d stands for the diameter of the hemisphere
If the diameter of the hemisphere is 30 cm, for example, then it has a volume of:
1/12 x 3.14 x (30cm)³ = 0.2616 x 27000 cm³ = 7063.2 cm³
The hemisphere has a capacity of about 7 liters.
The truncated cone
The following formula V=[( pi x h) : 3] x (r1² + r1 x r2 + r2²) applies here. The upper diameter of the pot and the lower diameter of the pot must be measured.
Example:
Diameter at the top 20 cm, i.e. radius r2 = 10 cm
Diameter below 15 cm, i.e. radius r1 = 7.5 cm
Pot height 20 cm
Calculation:
V= [( pi x h) : 3] x (r1² + r1 x r2 + r2²)
= [(3.14 x 20cm): 3] x (7.5²cm² + 7.5cm x 10cm + 10²cm²)
= [62.8 cm : 3] x (56.25 cm² + 75 cm² + 100 cm²)
= 20.9cm x 231.25cm²
= 4833.125cc
The flower pot has a capacity of almost 5 liters.