Geometry
Curved side and total surface area
Both come from the same inputs as the volume but are measured in square units. The two ends are the base area counted twice.
The Formula
Lateral A = 2 pi r h, total A = 2 pi r h + 2 pi r^2
Both come from the same inputs as the volume but are measured in square units. The two ends are the base area counted twice.
| Symbol | Meaning | Unit | Notes |
|---|---|---|---|
| Lateral A | Area of the curved side only | square units | Unrolls into a rectangle of width 2 pi r and height h. |
| Total A | Curved side plus both circular ends | square units | The quantity you need for material or paint estimates. |
| r | Radius shared with the volume formula | length | Same value as in V = pi r squared h; never substitute the diameter here. |
What Each Symbol Means
Lateral Asquare units
Area of the curved side only
Unrolls into a rectangle of width 2 pi r and height h.
Total Asquare units
Curved side plus both circular ends
The quantity you need for material or paint estimates.
rlength
Radius shared with the volume formula
Same value as in V = pi r squared h; never substitute the diameter here.
See It Worked With Real Numbers
A formula on its own does not tell you which number goes where. The how to calculate the volume of a cylinder page applies this equation to a concrete case, shows every intermediate step, and names the mistakes that produce a wrong answer even when the algebra is right.
Where This Formula Appears
This equation is the working core of How To Calculate The Volume Of A Cylinder, filed under Math. Every number the guide produces comes from substituting into this one line.