Cylinder Volume Calculator
Tank, well, and pipe volume in liters and gallons from diameter and height.
What it does
Cylindrical tanks, wells, and pipes all share one volume: the circular base area stretched along the height. Rain barrels, well casings, and culverts differ only in which diameters and lengths feed the same pi.
The tool above takes diameter with height in metric or imperial. It returns volume in both systems with the water weight beside them.
The default of 50 cm diameter by 100 cm height holds 196.35 L (0.196 m3), weighing 196.3 kg full of water. The imperial mirror of 19.69 by 39.37 in holds 51.9 gal weighing 433.1 lb.
The formula follows open geometry textbook treatments with course material matching each rearrangement. Both write V as pi r squared h and solve backwards for missing dimensions the same way.
How to use
- Pick centimeters or inches for both measures.
- Measure diameter across the face, not around it.
- Measure height along the axis, length for pipes.
- Read volume first in your system.
- Read water weight before moving full vessels.
Formula
- d
- Diameter across the circular face.
- h
- Height or pipe length along the axis.
- pi
- 3.14159..., the circle constant.
Imperial converts to metric first (1 in = 2.54 cm), then runs one path, so systems agree. Inside diameters give true capacity; outside diameters include the wall.
Worked example
Example: 50 cm by 100 cm tank
Metric defaults: diameter 50 cm, height 100 cm.
- Radius: 50 / 2 = 25 cm.
- Base: pi x 25 x 25 = 1,963.5 cm2.
- Stretch: 1,963.5 x 100 = 196,350 cm3.
- Liters: 196,350 / 1000 = 196.35 L (0.196 m3).
- Tool shows 196.35 L, 0.196 m3, 196.3 kg of water.
Reference table
| Vessel | Volume | Water |
|---|---|---|
| 10 cm by 20 cm jar | 1.57 L | 1.6 kg of water |
| 50 cm by 100 cm tank | 196.35 L | 196.3 kg of water |
| 22.5 in by 33.5 in drum | 57.66 gal | 481.2 lb of water |
Limits
- Straight cylinders only; cones and spheres need their pages.
- Inside diameters give capacity; outside adds the wall.
- Heaped or half full vessels need level math.
- Wall thickness and fittings displace a little volume.
Common mistakes
- Feeding circumference where diameter belongs.
- Squaring the diameter instead of the radius.
- Mixing cm with inches mid formula.
- Ordering by outside size for tight fits.
- Lifting full vessels rated by empty weight.
Try it yourself
Quick checks. Answers sit tucked under each question.
10 cm diameter, 20 cm tall?
pi x 25 x 20 = 1.57 L (0.002 m3).
Pools too?
Use the pool volume page: slopes and steps break cylinder math.
Find height for 100 L at 40 cm diameter?
Base 1,256.6 cm2, so 100,000 / 1,256.6 = 79.6 cm tall.
Questions
What is the cylinder volume formula?
Pi times radius squared times height. Diameter halves to radius first.
How many gallons is 196 L?
About 51.9 gal (divide by 3.78541).
How heavy is a full tank?
A liter of water weighs a kilo: 196.35 L is 196.3 kg plus the vessel.
Diameter or radius?
This page asks diameter and halves it inside. Halve twice and the answer quarters.
Horizontal tanks?
Full volume matches; partial levels need segment math instead.
Pipes in gallons per foot?
Run diameter with 12 in (30.48 cm) height: that foot of pipe is the per foot volume.