Partial and total volume of a horizontal cylindrical tank from diameter, length and liquid fill depth — exact circular-segment geometry, the basis of a real tank dip/strapping chart.
Standard method — stated scope limits apply
Tank & Fill Depth
Enter tank dimensions and fill depth.
About This Calculation
A horizontal cylindrical tank's volume as a function of liquid depth is NOT linear — unlike a vertical tank where volume scales directly with height, a horizontal tank's cross-section is a circular segment whose area changes nonlinearly with fill depth, meaning the same depth increase near the bottom or top of the tank represents far less volume change than the same depth increase near the middle. This calculator produces the actual dip-chart relationship (volume vs. depth) for a horizontal cylindrical tank, accounting for this geometry directly rather than assuming a linear approximation that would be genuinely wrong.
Frequently Asked Questions
Why is horizontal tank volume-vs-depth nonlinear when vertical tank volume is linear?
A vertical tank’s horizontal cross-section (a circle) stays the same area at every height, so volume simply scales with height — a horizontal tank’s cross-section at any given depth is a circular SEGMENT, and segment area changes nonlinearly with depth (fastest change near the tank’s midpoint, slowest near the very top and bottom), which is the actual geometric reason the relationship isn’t a straight line.
Why does this matter for a dipstick-based level gauge?
A dip chart converts a measured dip (physical depth) into volume — if the underlying volume-depth relationship were assumed linear when the tank is actually horizontal, every depth reading except at exactly 50% full would give a genuinely wrong volume, with the error being largest near the top and bottom of the tank where the true curve deviates most from a straight line.
Does a tank with hemispherical or dished heads need a different calculation than a flat-ended cylinder?
Yes — the head shape adds its own volume contribution as a function of depth, following different geometry than the cylindrical shell section, so a tank with dished, hemispherical, or elliptical heads needs those head volumes calculated and added separately, not just the cylindrical body treated in isolation.