Tank Volume & Partial Fill Calculator
Calculate liquid volume in a horizontal cylindrical tank with flat, hemispherical or 2:1 ellipsoidal ends.
“The dip reading is 400 mm. How many litres are actually left in the horizontal tank?”
Horizontal tank fill reference
V = A_segment × L_cylA = r² cos⁻¹((r−h)/r) − (r−h)√(2rh−h²)V_total = cylinder + head volumesFor hemispherical and ellipsoidal heads, the calculator uses a geometric numerical integration rather than a crude percentage approximation.
Horizontal cylindrical tank with liquid depth
Horizontal tank geometry
The straight length excludes the heads.
Estimated liquid inventory
Actual nozzle intrusions, dead volume, wall thickness, head knuckle geometry, tank slope and calibration tolerances are not included.
The cylindrical portion uses the circular-segment area. Curved heads are integrated numerically as idealised ellipsoids of revolution.
Save the calculation, not just the number.
Copy a permalink that reloads these inputs, or download a PDF record with inputs, visible results, assumptions, a sensitivity note, date and disclaimer.
A calculator can show the arithmetic. It cannot establish every requirement that applies.
Confirm the actual equipment, loading, materials, condition, jurisdiction, contractual requirements, standard edition and current project documentation before using the result for design, repair, testing or lifting decisions.
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