Tank Volume Calculator
Model tank capacity from internal dimensions, then optionally calculate liquid volume at a measured fill depth. Horizontal cylinders use circular-segment geometry instead of a simple depth percentage.
How to use the Tank Volume Calculator
Enter tank shape, required internal dimensions in feet, and current liquid depth in feet.
Review internal versus nominal dimensions, wall thickness, end-cap shape, dead volume, tilt, and manufacturer capacity.
Read full capacity, current liquid volume, fill percentage, and full capacity in liters.
Formula
Rectangular capacity = length × width × height. Vertical cylinder = πr²h. A horizontal cylinder filled to depth d uses segment area r² arccos((r − d) ÷ r) − (r − d)√(2rd − d²), multiplied by tank length.
Example
A 4 ft diameter vertical cylinder with a 6 ft height has capacity π × 2² × 6 = 75.398 ft³ before conversion to gallons.
Assumptions and limitations
- The tank is level and matches the selected ideal geometry; fittings, rounded corners, dished heads, and inaccessible volume are excluded.
- Tank Volume Calculator treats the entered values as estimates and does not infer missing project, account, or personal details.
- Calculations retain working precision except where the cited method requires an intermediate rounding step; displayed values are then formatted separately. Source rules and dated rates must be rechecked when they change.
Sources
- National Institute of Standards and Technology: SI Units — LengthLength, area, volume, and unit-conversion conventions. Reviewed 2026-08-14.
- OpenStax: College Algebra 2eAlgebraic, ratio, radical, equation, and function formulas. Reviewed 2026-08-14.
- National Institute of Standards and Technology: Circumference, Area and VolumeOfficial formula, rate, or program guidance used by this calculator. Reviewed 2026-08-14.
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Frequently asked questions
How does the Tank Volume Calculator work?
Rectangular capacity = length × width × height. Vertical cylinder = πr²h. A horizontal cylinder filled to depth d uses segment area r² arccos((r − d) ÷ r) − (r − d)√(2rd − d²), multiplied by tank length.
What information should I enter in the Tank Volume Calculator?
Enter tank shape, required internal dimensions in feet, and current liquid depth in feet, then verify internal versus nominal dimensions, wall thickness, end-cap shape, dead volume, tilt, and manufacturer capacity.
What should I verify before using this Tank Volume Calculator result?
The tank is level and matches the selected ideal geometry; fittings, rounded corners, dished heads, and inaccessible volume are excluded.
Reviewed 2026-08-14 · 1.0.0 · content-2026-08-14 · Trusty Calculator Editorial Team