How this calculator works
Rectangular and vertical cylindrical tanks have constant horizontal area, so stored volume grows linearly with depth. A horizontal cylinder uses a circular segment at the measured depth, multiplied by length. A sphere uses spherical-cap volume. Reverse mode searches within the physical depth range. The calibration table and chart use internal dimensions, metres and litres. Domed ends, baffles, internal piping and tilted tanks are outside these ideal shapes.
Formula
Rectangular V = LWh; vertical cylinder V = pi r^2 h; horizontal cylinder V = L[r^2 acos((r-h)/r) - (r-h)sqrt(2rh-h^2)]; sphere V = pi h^2(r-h/3). Fill fraction = liquid volume / full capacity.
Worked example
A flat-ended horizontal cylinder 2 m in diameter and 3 m long holds 9.42478 m3 when full. At 1 m liquid depth it is half full, containing 4.71239 m3. A 2 x 3 x 4 m rectangular tank at 1 m depth contains 6 m3.
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Frequently asked questions
Is half the depth always half the volume?
At exactly half depth, these symmetric shapes are half full. At other depths, horizontal cylinders and spheres have a nonlinear depth-volume relationship.
Which dimensions should I measure?
Use internal dimensions and measure depth from the inside bottom. Nominal outside dimensions overstate capacity when walls are thick.
Does the chart establish a certified tank calibration?
No. It is a geometric reference. Trade measurement or precise inventory may require a measured calibration that includes actual tank shape and installation.