1. Choose your tank
Tank type
Horizontal cylinder — flat ends
All dimensions use the selected unit. Changing units converts your entries.
2. Tank volumes
Enter your dimensions and select Calculate volume.
Remaining space is geometric free volume; required operating headspace is not deducted.
Equations and assumptions
Use internal dimensions. Liquid has a level, horizontal surface. Cylinders have flat ends; horizontal cylinders must be level. The cone is a complete cone with its point facing down. Illustrations are schematic.
| Tank | Total capacity | Liquid volume at level h |
|---|---|---|
| Rectangular | LWH | LWh |
| Vertical cylinder | πr²H | πr²h |
| Horizontal cylinder | πr²L | L[r² arccos((r − h)/r) − (r − h)√(2rh − h²)] |
| Sphere | 4πr³/3 | πh²(r − h/3) |
| Cone, point down | πr²H/3 | (πr²H/3)(h/H)³ |
r = D/2. h is measured vertically from the lowest internal point. L is cylinder length or rectangular length; W is rectangular width; H is tank height. Curved tanks do not generally fill in direct proportion to liquid height.
Excludes dished or hemispherical heads, cone-bottom cylinders, sloped installation, wall thickness, and internal obstructions. This is a geometric capacity calculation, not a tank calibration or pressure design tool.
Formula references: Wolfram MathWorld: circular segment and spherical cap.