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Level Measurement · Free Calculator

Spherical Tank Volume Calculator

Calculate liquid volume in a spherical tank (such as an LPG sphere) at any level, with a strapping table for transmitter characterisation.

SpherePartial volumeStrapping tableLPG storage
Liquid volume113.1 m³
Percent of volume21.60 %
Percent of level30.00 %
Total volume523.6 m³
How this result was calculated
  1. V = π × h² × (3R − h) ÷ 3 = 113.1 m³

Level to volume strapping table

Level %LevelVolumeVolume %
0 %0 m0 m³0.0 %
10 %1 m14.661 m³2.8 %
20 %2 m54.454 m³10.4 %
30 %3 m113.1 m³21.6 %
40 %4 m184.31 m³35.2 %
50 %5 m261.8 m³50.0 %
60 %6 m339.29 m³64.8 %
70 %7 m410.5 m³78.4 %
80 %8 m469.14 m³89.6 %
90 %9 m508.94 m³97.2 %
100 %10 m523.6 m³100.0 %
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Spherical Cap Volume

V = π × h² × (3R − h) ÷ 3
Total = π × D³ ÷ 6

Worked example

A 10 m sphere filled to 3 m holds π × 9 × (15 − 3) ÷ 3 = 113.1 m³, only 21.6 % of its 523.6 m³ capacity at 30 % level.

Key insight: volume changes slowly near the top and bottom of a sphere and fastest at the middle. Configure a strapping curve in the level transmitter or DCS so operators see true volume.
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Frequently Asked Questions

How do I calculate the volume of a partly filled sphere?

Use the spherical cap formula V = πh²(3R − h)/3, where h is the liquid depth and R the radius.

What is the volume at 50 % level?

Exactly half, because a sphere is symmetrical about its middle.

Does this include nozzles and internals?

No. For custody transfer use a calibrated strapping table from tank calibration.

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